Being flummoxed by a student question was the inspiration for a teaching metaphor
Keith S. Taber
An artist's impression of the author being lost for words (Image actually by Christian Dorn from Pixabay)
In my teaching on the 'Educational Research' course I used to present a diagram of a shape something like the lemniscate – the infinity symbol, ∞ – and tell students that was the shape their research project and thesis should take. I would suggest this was a kind of visual metaphor.
This may seem a rather odd idea, but I was actually responding to a question I had previously been asked by a student. Albeit, this was a rather deferred response.
'Lost for words'
As a teacher one gets asked all kinds of questions. I've often suggested that preparing for teaching is more difficult than preparing for an examination. When taking an examination it is usually reasonable to assume that the examination question have been set by experts in the subject.
A candidate therefore has a reasonable chance of foreseeing at least the general form of the questions that night asked. There is usually a syllabus or specification which gives a good indication of the subject matter and the kinds of skills expected to be demonstrated – and usually there are past papers (or, if not, specimen papers) giving examples of what might be asked. The documentation reflects some authority's decisions about the bounds of the subject being examined (e.g., what counts as included in 'chemistry' or whatever), the selection of topics to be included in the course, and the level of treatment excepted at this level of study (Taber, 2019). Examiners may try to find novel applications and examples and contexts – but good preparation should avoid the candidate ever being completely stumped and having no basis to try to develop a response.
However, teachers are being 'examined' so to speak, by people who by definition are not experts and so may be approaching a subject or topic from a wide range of different perspectives. In science teaching, one of the key issues is how students do not simply come to class ignorant about topics to be studied, but often bring a wide range of existing ideas and intuitions ('alternative conceptions') that may match, oppose, or simply be totally unconnected with, the canonical accounts.
This can happen in any subject area. But a well prepared teacher, even if never able to have ready answers to all question or suggestions learners might offer, will seldom be lost for words and have no idea how to answer. But I do recall an occasion when I was indeed flummoxed.
I was in what is known as the 'Street' in the main Faculty of Education Building (the Donald McIntyre Building) at Cambridge at a time when students were milling about as classes were just ending and starting. Suddenly out of the crowd a student I recognised from teaching the Educational Research course loomed at me and indicated he wanted to talk. I saw he was clutching a hardbound A4 notebook.
We moved out of the melee to an area where we could talk. He told me he had a pressing question about the dissertation he had to write for his M.Phil. programme.
"What should the thesis look like?"
His question sounded simple enough – "What should the thesis look like?"
Now at one level I had an answer – it should be an A4 document that would be eventually bound in blue cloth with gold lettering on the spine. However, I was pretty sure that was not what he meant.
What does a thesis look like?
I said I was not sure what he meant. He opened his notebook at a fresh double page and started sketching, as he asked me: 'Should the thesis look like this?' as he drew a grid on one page of his book. Whilst I was still trying to make good sense of this option, he started sketching on the facing page. "Or, should it look like this?"
I have often thought back to this exchange as I was really unsure how to respond. He seemed no more able to explain these suggestions than I was able to appreciate how these representations related to my understanding of the thesis. As I looked at the first option I was starting to think in terms of the cells as perhaps being the successive chapters – but the alternative option seemed to undermine this. For, surely, if the question was about whether to have 6 or 8 chapters – a question that has no sensible answer in abstract without considering the specific project – it would have been simpler just to pose the question verbally. Were the two columns (if that is what they were) meant to be significant? Were the figures somehow challenging the usual linear nature of a thesis?
I could certainly offer advice on structuring a thesis, but as a teacher – at least as the kind of constructivist teacher I aspired to be – I failed here. I was able to approach the topic from my own perspective, but not to appreciate the student's own existing conceptual framework and work from there. This if of course what research suggests teachers usually need to do to help learners with alternative conceptions shift their thinking.
Afterwards I would remember this incident (in a way I cannot recall the responses I gave to student questions on hundreds of other occasions) and reflect on it – without ever appreciating what the student was thinking. I know the student had a background in a range of artistic fields including as a composer – and I wondered if this was informing his thinking. Perhaps if I had studied music at a higher level I might have appreciated the question as being along the lines of, say, whether the should the thesis be, metaphorically speaking, in sonata form or better seen as a suite?
I think it was because the question played on my mind that later, indeed several years later, I had the insight that 'the thesis' (a 'typical' thesis) did not look like either of those rectangular shapes, but rather more like the leminscape:
A visual metaphor for a thesis project (after Taber, 2013)
The focus of a thesis
My choice of the leminscate was because its figure-of-eight nature made it two loops which are connected by a point – which can be seen as some kind of focal point of the image:
A thesis project has a kind of focal point
This 'focus' represents the research question or questions (RQ). The RQ are not the starting point of most projects, as good RQ have to be carefully chosen and refined, and that usually take a lot of reading around a topic.
However, they act as a kind of fulcrum around which the thesis is organised because the sections of the thesis leading up to the RQ are building up to them – offering a case for why those particular questions are interesting, important, and so-phrased. And everything beyond that point reflects the RQ, as the thesis then describes how evidence was collected and analysed in order to try to answer the questions.
Two cycles of activity
A thesis project cycles through expansive and focusing phases
Moreover, the research project described in a thesis reflects two cycles of activity.
The first cycle has an expansive phase where the researcher is reading around the topic, and exposing themselves to a wide range of literature and perspectives that might be relevant. Then, once a conceptual framework is developed from this reading (in the literature review), the researcher focuses in, perhaps selecting one of several relevant theoretical perspectives, and informed by prior research and scholarship, crystallises the purpose of the project in the RQ.
Then the research is planned in order to seek to answer the RQ, which involves selecting or developing instruments, going out and collecting data – often quite a substantive amount of data. After this expansive phase, there is another focusing stage. The collected data is then processed into evidence – interpreted, sifted, selected, summarised, coded and tallied, categorised – and so forth – in analysis. The data analysis is summarised in the results, allow conclusions to be formed: conclusions which reflect back to the RQ.
The lemniscate, then, acts a simple visual metaphor that I think acts as a useful device for symbolising some important features of a research project, and so, in one sense at least, what a thesis 'looks' like. If any of my students (or readers) have found this metaphor useful then they have benefited from a rare occasion when a student question left me lost for words.
I recently listened to NASA's Nicky Fox being interviewed about the Parker Solar Probe which (as the name suggests) is being used to investigate the Sun.
There is a website for the project which, when I accessed it (28th December 2021), suggested the spacecraft was 109 279 068 km from the Sun's surface (which I must admit would have got a marginal comment on one of my own student's work along the lines "is the Sun's surface so distinctly positioned that this level of precision can be justified?") and travelling at 57 292 kph (kilometers per hour). This unrealistic precision derives from the details being based on "mission performance modeling [sic] and simulation and not real-time data…" Real-time data is not necessarily available to the project team itself – the kind of shielding needed to protect the spacecraft from such extreme conditions also creates a challenge in transmitting data back to earth.
But the serious point is that returning to the website at another time it is possible to see how the probe's speed and position have changed (as shown on 'the Mission' webpage – indeed by the time I took the 'screenshot' it had moved about 7000 km), as the spacecraft moves through a sequence of loops in space orbiting the Sun on a shifting elliptical path that takes it periodically very close (very close, in solar system terms, that is) to the sun. Like any orbiting body, the probe will be moving faster when closest to the sun and slowest when furthest from the sun. (The balance shifts between its kinetic and potential energy – as it works to move away against the sun's gravity when receding from it 1.)
Touching the Sun
Publicity still from the Danny Boyle film 'Sunshine'
Getting too close the Sun – with its high temperature, the 'solar wind' of charged particles emitted into space, occasional solar flares, and the high flux of radiation from across the electromagnetic spectrum – is very dangerous, making the design and engineering of any craft intended to investigate our local star up close very challenging. A key feature is a protective heat shield facing the Sun . This was the premise of the sci-fi film 'Sunshine' 2.
For the Parker probe
"the spacecraft and instruments will be protected from the Sun's heat by a …11.43 cm carbon-composite shield, which will need to withstand temperatures outside the spacecraft that reach nearly …1,377 degrees Celsius"
"At closest approach to the Sun, while the front of Parker Solar Probe' solar shield faces temperatures approaching … 1,400° Celsius, the spacecraft's payload will be near room temperature, at about [29˚C.]."
http://parkersolarprobe.jhuapl.edu
Note: Dr Fox is NOT reporting from the Parker Solar Probe – just pictured in front of an image of the sun (Dr Fox's profile on NASA website)
Dr Fox, who is Director of NASA's Heliophysics [physics of the Sun] Division, was being interviewed about data released from an earlier close approach on a BBC Science in Action podcast.
"The Parker Solar probe continues its mission of flying closer and closer to the sun. Results just published show what the data the probe picked up when it dipped into the surrounding plasma. NASA's Nicky Fox is our guide."
The project is framing that event as when, "For the first time in history, a spacecraft has touched the Sun". Although the visible surface of the sun has a temperature of about 6000K (incredibly hot by human standards), the temperature of the 'atmosphere' or corona around it is believed to reach several million Kelvins. On the programme, Dr Fox was asked about how the spacecraft could survive in the sun's corona, given its extremely high temperatures.
A teaching analogy?
In response she used an analogy from everyday experience:
"We talk about the plasma being at a couple of million degrees, it's like putting your hand inside an oven, and you don't touch anything. You won't burn your hand, you'll feel some heat but you won't actually burn your hand, and so the solar wind itself, or the corona, is a very tenuous plasma, there are just not that many particles there. So, even though the whole atmosphere is at about two million degrees, the number of particles that are coming into contact with the spacecraft are [sic] very small.
The temperatures that we have to deal with are about fourteen, fifteen hundred degrees Celsius, at the maximum, which is still hot, don't…let me kid you, that's still hot, but it is not two million degrees."
Dr Fox interviewed on Science in Action
Analogies are commonly used in science, science communication and science education as one means of 'making the unfamiliar familiar' by showing how something novel or surprising is actually like something the audience is already aware of and comfortable with.
If the probe had been dipped in a molten vat of some hypothetical refractory liquid at two million degrees it would have quickly been destroyed. But because the Corona is not only a plasma (an 'ionised gas')3, but a very tenuous one, this does not happen. NASA sending the probe into the corona is similar to putting one's hand in the oven when cooking. If you touch the metal around the outside you will burn yourself, but you are able to reach inside without damage as long as you do not touch the sides – as although the air in the oven can get as hot as the metal structure, it has a very low particle density compared with a solid metal. So, your hand is in a hot place, but is not in contact with much of the hot material.
Do not try this at home – at least not unless you are quick
Of course, this is not the whole story. You can reach in the oven to put something in or (with suitable protection) take something out, but you cannot safely leave your hand in there for any length of time.
When two objects at different temperature are placed in contact, heating will occur with 'heat' passing from the hotter to colder object until they are in thermal equilibrium (i.e., at the same temperature). But this is not instantaneous – it takes time.4 If the Parker Solar Probe had been flown into the Sun's atmosphere and left there it would have been heated till it eventually matched the ambient temperature (not 'just' 1400˚C) regardless of how effective a heat shield it had been given. Or rather, it would have been heated till its substance reached the ambient temperature, as it would have lost structural integrity long before this point.
Of course, the probe has been designed to spend some time in the coronal atmosphere collecting data, but to only dip in for short visits, as NASA is well aware that it would not be wise to leave one's hand in the oven for too long.
Note:
1 This at least is the description based on Newtonian physics. There is an attractive, gravitational force between the Sun and the probe. As the spacecraft moves towards the sun it accelerates, and then its momentum takes it away, being decelerated by gravity.In this model gravity is a force between two bodies. (The path is actually more complex than this, as it has been designed to fly past Venus several times to adjust its trajectory round the Sun.)
In the model offered by general relativity the probe simply moves in a straight line through space which has a complex geometry due to the presence of matter/energy: a straight line which seems to us to be a shifting series of ellipses. Gravity here is best understood as a distortion from a 'flat' space. Perhaps it is clear why for most purposes scientists stick with the Newtonian description even though it is no longer the account considered to best describe nature.
2 The movie poster gives a slight clue to the hazards involved in taking a manned mission to the Sun!
3 Plasma is considered a fourth state of matter: solid, liquid, gas, plasma. The expression that 'a plasma is an ionised gas' may suggest plasma is a kind of gas, but then we might also say that a gas is a boiled liquid or that a liquid is melted solid! So, perhaps what we should say is that a plasma [gas/liquid] is what you get when you ionise [boil/melt] a gas [liquid/solid].
4 In theory, modelling of such a process suggests it takes an infinite time for this to occur. 5 In practice, the temperatures become close enough that for practical purposes we consider thermal equilibration to have occurred.
5 This is an example of a process that can be understood as having a negative feedback cycle: temperature difference drives the heat flow, which reduces temperature difference, which therefore also reduces the driver for heat flow; so the rate of heat flow is reduced, so therefore the rate of temperature change is reduced… This is a similar pattern to radioactive decay – both follow an 'exponential decay' law.
Some responses to the "Initial teacher training market review"
A 'market' review
Image by Pexels from Pixabay
The UK Government's Department for Education (responsible for the school system in England) is currently undertaking what it called a 'market review' of initial teacher education (ITE) or initial teacher 'training' as it prefers to describe ite. (Arguably, 'education' suggests broad professional preparation for someone who will need to make informed decisions in complex situations, whereas 'training' implies learning the skills needed for a craft.)
The aims of the review are certainly unobjectionable:
The review has aimed to make well informed, evidence-based recommendations on how to make sure:
• all trainees receive high-quality training • the ITT market maintains the capacity to deliver enough trainees and is accessible to candidates • the ITT system benefits all schools1
Despite such intentions clearly being laudable, the actual proposals (which, inter alia, can be seen as looking to further increase central government control over the professional preparation of teachers) raised concerns among many of those actually involved in teacher education.
The consultation
There was a public consultation to which all interested were invited to respond. Since the consultation closed, the Secretary of State (i.e., senior minister) for Education has changed, so we await to see whether this will derail the review.
The review is wide ranging, but there is a widespread view that once again government is seeking to reduce the influence of academic education experts (see for example, 'Valuing the gold standard in teacher education'), and my colleagues still working in university-school based ITE partnerships certainly felt that if all the proposals were brought to fruition such partnership would be at risk. Not that Universities would not be able to contribute, but they would not be able to do so in a way that allowed full quality control and proper planning and sustainable commitment.
My own University, Cambridge, has suggested
We cannot, in all conscience, envisage our continuing involvement with ITT should the proposals be implemented in their current format.
Some discussion on one teachers' email list I subscribe to, provoked me me decide to look back at my own consultation responses.
A selective response – and a generic default hole-filler
I have not worked in I.T.E. for some years, and so did not feel qualified to comment on all aspects of the review. However, there were some aspects of the plans (or at least my interpretation of what was intended) that I felt would put at risk some of the strongest and most important aspects of high quality teacher preparation.
As being able to submit a response to the consultation required providing a response at every section (a cynic might suggest that expecting full completion of such a long consultation document is a disincentive for most people to contribute), I used a generic statement to cover those questions where I did not feel I had anything informed and useful to say:
I am aware of concerns raised in responses by the Russell group of Universities, the University of Cambridge (of which I am an emeritus officer), and Homerton College, Cambridge (of which I am a senior member). I concur with these concerns, and rather than seek to reproduce or mirror all of their comments (already available to you), I refer you to those responses. Further, I am offering some specific comments on particular issues where I have strong concerns based on my past experiences as a PGCE student teacher; as a teacher in comprehensive secondary schools; as a school/college-based mentor supporting graduates preparing for teaching in schools and also in a further education context; as a researcher exploring aspects of student learning and the teaching that supports it; as a lecturer and supervisor on initial teacher education courses as part of University-School training partnerships; as a supervisor for teachers in post undertaking school-based research; as an advisor to schools undertaking context-directed research; and as a lecturer teaching graduates how to undertake research into educational contexts.
Here are my more specific responses highlighting my particular concerns:
Individual differences
Having worked in initial teacher education as well as having been a school teacher, I am well aware that one of the most important things anyone working in the education sector has to appreciate is individual differences – between pupils, between teachers, between classes, between schools, and between new-entrants. Too much focus on uniformity is therefore unwelcome and likely to reduce the quality of the highest provision which takes this into diversity into account, Similarly, genuinely 'rigorous' sequencing of the educational experience will be responsive to individual needs and that would be welcome. However, uniform and inflexible sequencing, which would be far from rigorous, would be damaging.
Being equipped to engage with research
I am aware that the diversity in routes for new entrants now available has reduced the quality of training experience available to some new teachers. In particular, the fully professional teacher has to be a critical reader of research, and to have the tools and confidence to undertake their own small-scale context based enquiry to develop their own practice.
This is essential because the research shows clearly that whilst it is sometimes possible to identify some features of best practice that generalise across most teaching contexts, this is by no means always the case. Teaching and learning are highly complex phenomena and are strongly influenced by contextual factors. So, what has been found to 'normally' work best will not be the best approach in all teaching contexts. Teachers needs to be able to read research claims critically
(there are always provisos
most studies are small-scale where strict generalisation is simply not possible,
few studies are sufficiently supported with the resources to test ideas across a wide range of contexts; and
as randomisation {a critical aspect of true experimental research} is seldom possible, and
there is seldom the information or means to characterise populations sufficiently to build representative samples;
moreover the complexity of educational contexts does not allow the identification (let alone control) of all relevant variable, and
there are some key known factors which influence results when double-blind methods are not viable
– a situation that is very common when testing innovations in educational practices as teachers and learners are usually well aware of deviations from normal practice)
and identify the most promising recommendations when taking into account their own teaching context (i.e., what is referred to as reader or naturalistic generalisation) and test out ideas in their own classrooms, and iteratively develop their own practice.
Sadly, whilst the M-level PGCE type programmes usually support new teachers in introducing these skills, this does not seem to necessarily be the case on some other routes.
On 'intensive' practice placements
I consider this is a misguided notion based on a flawed conceptualisation of teaching and teacher skills. It is certainly the case that generally speaking teachers develop their skills over time with greater teaching experience, and that all other things being equal, the more direct teaching experience a new entrant has during the period of initial teacher education the better, as long as this is productive experience.
However, teaching is a highly complex activity that requires making myriad in the moment decisions in response to interactions with unique classes of unique people. The quality of those decisions tends to increase over time with experience, but only if the teacher is well prepared for the teaching in terms of subject knowledge, general and specialist pedagogic knowledge, and knowledge of the particular learners.
This requires that the teacher has extensive preparation time especially when new to teaching a topic, age, group or pedagogic approach, and opportunities for productive debrief and reflection. Given the intensity of teaching as an experience, it is much better for new entrants to initially focus on parts of lessons with plenty of opportunity for preparation and reflection than to too quickly progress to whole lessons where much of the experience will not be fully processed before moving on. Similarly, it is better that new teachers have sufficient time between classes to focus intensely on those classes rather than be moving directly from class to class.
In the same way, the programmes that allow regular movements between the teaching context and an HEI or similar context offer an ideal context for effective learning. The intense focus on the school is broken up by time in faculty (still focused, but as a student without the intense scrutiny in school), where there are extensive opportunities for peer support (especially important given the extreme highs and lows often experienced by new teachers).
Partnerships of Universities with Schools offer new entrants complementary expertise, and opportunities for 'iteration' – moving between the 'graduate student' and 'teaching department member' contexts 2 (Figure 1 from Taber, 2017)
This is also critical for developing teaching that is informed by research-informed and evidence-based theories and constructs. Being taught 'theory' in an academic context, and expecting such content to be automatically applied in a teaching context is unrealistic – rather the new teacher has to learn to conceptualise actual classroom experience in terms of the theory, and to see how to apply the theory in terms of actual teaching experience. 2
This learning is best supported by an iterative process – where there are plenty of opportunities to reflect on and analyse experience, and compare and discuss experiences with peers, as well as with mentors, other experienced teachers, and with academic staff. Over time, as new teachers build experiences, especially ones they recognise as productive and successful, they will come to automatically apply ideas and skills and techniques, and will be able to 'chunk' component teaching moves into longer sequences – being able to work effectively for sequences of whole classes, with less reflection time, and less explicit support. 3
The aim is for the new teachers to be able to prepare, teach, assess, on something approaching a teaching timetable whilst working in school full-time. However, efforts to move to such a state too quickly will [be counter-productive] for many potentially excellent teachers, and will likely increase drop-out rates.
Ultimately, the quality of the teaching experience, and the ability to manage increasing workload according to individual needs, is what is important. Any attempts to increase the intensity of the teaching placements, or to accelerate the rate at which new teachers take on responsibility without recourse to individual circumstances is likely to be counterproductive in terms of retention, and the quality of the 'training' experience in supporting the development of excellent teachers.
I am very pleased that I would not be 'training' nor still working in teacher education under such expectations as I think the incidents of crises, mental health issues, and drop-out, would be likely to increase.
On common timetables for progress
As suggested above, any attempt to tightly quantify these things would be misplaced as it removes the ability of providers to manage the process to seek the best outcomes for individual trainees, and it ignores the responsibilities of teachers and schools to ensure that trainees are only given responsibilities as and when they are ready.
Please remember that every class taught by a trainee contains children or young people who are required to be in school and are entitled to be taught by someone who
is prepared for class,
confident they are ready to teach that class, and
is not under such intense stress that they cannot perform to their potential.
You have a responsibility to consider the pupils as well as to your 'market'.
On applying research evidence
A postgraduate award is meant to include a strong research component. As suggested in earlier comments, it is essential for the fully professional teacher who will need to make informed decisions about her own classroom practice to be be provided with the skills to access research (including understanding strengths and weaknesses of methodology), critique it, evaluate its potential relevance to the immediate teaching and learning contexts, and to evaluate it in the context. Many PGCE-MEd and PGCE-MA programmes already support this.
I totally agree that this should be provided to all new trainees, and would have thought there are enough HEIs with expertise in educational research for this to be possible (as it is on the PGCE-M route already). However, it is not enough to simply provide teachers the skills, they also have to have
access to research publications,
time to
read them and
undertake small-scale context-directed enquiry, and
to give them the confidence that this aspect of professional practice is recognised and appreciated.
For example, a teacher has to know that if they are doing something differently to some government advice because they have looked at the research, considered it in relation to their specific context, and evaluated approaches in their own teaching context and concluded that for a particular class/course/students some approach other than that generally recommended is indicated, THEN this would be recognised (e.g., in Inspections) as praiseworthy.
On 'incentives that could encourage schools and trusts to participate in ITT'
I would think it is dangerous and perhaps foolish to add to schools' expected responsibilities where they do not welcome this.
On proposed reforms on the recruitment and selection process
To me, this seems to complicate matters for a PGCE applicant who at the moment has to only select a university-schools partnership.
Potential equality impacts
As discussed above, in my experience current arrangements, at least for the PGCE route, offer flexibility to meet the individual needs of a range of new entrants. My sense is the proposals would be unhelpful in this regard.
Comments on 'any aspect'
I was lucky enough to undertake my PGCE at a university that at the time was recognised as one with excellent provision in my teaching subjects (chemistry and physics, at Nottingham Trent). At that time the structure of the teaching placement (two isolated blocks, one of 4 weeks, one of 8 weeks) did not allow the kind of incredibly valuable iterative experience of moving between the university and school contexts I discuss above, and the teachers in the schools did not act as mentors, but merely handed over their classes for a period of time.
Otherwise I was very happy with my 'training' experience.
If (some) university-schools partnerships (such as that based at the University of Cambridge) are recognised as excellent, why change the system in ways that threaten those providers?
Despite this, I know some of our excellent new recruits went through serious periods of doubt and crises in their teaching due to the intense and highly skilled nature of the work. In the context where I was lucky enough to work, the structure of the training year and the responsive and interactive nature of managing the graduates in their work meant that nearly always these setbacks were temporary, and so could be overcome.
I am concerned that some of this good practice may not continue if some of the proposals in the review are carried through – and that consequently a significant number of potentially excellent new teachers will not get the support they need to develop at the pace that best matches their needs. This will lead to drop-out, and early burn-out – or potentially candidates doing enough to cope, without meeting the high standards they wish to set for themselves to the benefit of their pupils.
Keith S. Taber
1 It strikes me that the third bullet point might seem a little superfluous – after all, surely a system of initial teacher education that both maintains the supply of new teachers at the level needed (which in some subjects would be a definite improvement on the existing system) and ensures they all receive high quality preparation should inherently benefit all schools by making sure there was always a pool of suitably qualified and well-prepared teachers to fill teaching vacancies across the school curriculum.
Perhaps, however, this means something else – such as (in view of the reference to 'incentives that could encourage schools and trusts to participate in ITT' in the consultation) making sure all schools receive funding for contributing to the preparation of new teachers (by making sure all schools make a substantial contribution to the preparation of new teachers).
2 It strikes me that the way in which teachers in preparation are able to move back and forth between a study context and a practitioner context, giving opportunities to apply learning in practice, and to 'stand back' and reflect on and conceptualise that practice, reflects the way science proceeds – where theory motivates new practical investigations, and experience of undertaking the empirical enquiry informs new theoretical refinements and insights (which then…).
3 That is, the pedagogic principles which teachers are expected to apply when working with their students are, in general terms, just as relevant in their own professional education.
Work cited:
Taber, K. S. (2010). Preparing teachers for a research-based profession. In M. V. Zuljan & J. Vogrinc (Eds.), Facilitating effective student learning through teacher research and innovation (pp. 19-47). Ljubljana: Faculty of Education, University of Ljubljana.
The government are about to1 publish a white paper on education2 that will set out intentions for the future of teacher education (teacher 'training'). The expectation is that there will be a shift from University-based teacher education, to school-based training. By university-based, the government will mean such routes into teaching as the Post-graduate Certificate in Education, or PGCE, which has long been considered the major way of preparing to teach in secondary schools. However, such courses have not really been University-based for many years. Indeed, there are good reasons to believe that the PGCE represents a 'gold standard' in teacher preparation that has evolved towards an optimal mode of teacher preparation.
I was trained on a PGCE course about 30 years ago. At that time, I spent twice as much time in the University, as in schools. Moreover, the school-based practices were blocks of time in school, with minimal input from teaching staff, largely seen as an opportunity to practice the theoretical ideas being taught in the university lectures. The PGCE today is quite unlike this. The students admitted have good degrees in their disciplines – and, often, higher degrees – making them strong subject specialists. During the 36-week PGCE course these students spent two-thirds of their time working in schools. Moreover, this work is interspersed with time in the university in a schedule allowing university-based teaching to carefully support, prepare for, and allow careful reflection upon, school experience. University teaching is not lecturing about abstract theory, but introducing basic principles of learning and pedagogy, essential information about school structures and the curriculum, and a detailed induction into the nature of subject-specific pedagogy: things that the new teachers can apply directly in the classroom.
In the schools, where these 'trainees' spend most of their time, teachers act as their mentors and managers. Schools are partners with the university, and the teaching is shared between university and school staff. Unlike the 'being left to get on with it' mentality of teaching practice during my own training, these days the new teachers are carefully inducted, working alongside an experienced teacher who provides a structured introduction to teaching. Each trainee has a flexible, individualised learning plan, and negotiates with their mentor the rate at which they incrementally take on more responsibility for teaching classes. Trainees work within overlapping communities, as both members of school teaching departments and as part of a group of peers within their subject specialism, supported by an expert subject-specialist educator within the University. It offers the best of both worlds.
Figure 1 from Taber (2017)
In the past decade, the Post-graduate teaching certificate has really become a gilt-edged award, as courses have developed to reflect the Master's level status of the qualification, making sure that trainee teachers are working at the forefront of scholarship in their specialist area: science education, or maths education, or English education etc. In particular, PGCE courses provide trainees with the knowledge and skills that support classroom enquiry. Trainees undertake small-scale research projects during school placements, which ensure that they have the skills to critically draw upon existing research, and practically tackle problems in their own teaching. In my own institution, this work is impressive enough for us to have started an on-line journal to share PGCE student work with the teaching community (http://jotter.educ.cam.ac.uk/). This prepares PGCE graduates to be full professionals:
experts in their own discipline;
experts in the teaching of their subject;
and skilled to tackle problems, and find ways to improve their own practice.
Many teachers prepared through this route, go on to complete practice-based Master's degrees in education.
The excellence of many PGCE courses has been demonstrated not only by Ofsted inspections3, but also by the evaluations of both the graduates who take this route into teaching, and the schools in which they work. Over many years the PGCE has evolved to balance the needs of providing a solid grounding in the theoretical basis of effective teaching; positive and carefully supported classroom experience; induction into working in teams in schools, and levels of critical, analytical and research skills expected of a Master's level qualification. It is indeed the 'gold standard' in initial teacher education, and would only be sacrificed by a government who values a cheaply prepared and uncritical teaching force, over a body of professionals who are experts in teaching their subjects. Let us trust that does not prove to be the case.
Keith S. Taber
1 This piece was written in 2010 (when much of my teaching was on the PGCE programmes at Cambridge) and published as a blog posting on the Academia social media site (an edited version was also published as an opinion piece in 'Science Teacher Education'). Having recently had to think back to this in the context of the current 'market (sic) review' of Initial Teacher Education ('training') being carried out in England (see 'Reviewing initial teacher education'), I discovered that the original blog posting seems to have now disappeared from the www.
[Despite clear indications that the UK government wished to move the responsibility of initial teacher preparation away form Higher Education 'led' partnerships to school-based consortia, this only happened to some extent. If initial teacher education is considered a market, it was clear that many (if certainly not all) of the the 'clients' preferred to train in the university-school partnership routes. Whether the current [2021] 'market' review, which seems designed in part to make it more difficult for Universities to remain as key partners in I.T.E., will change this situation remains to be seen.]
2The importance of teaching. Presented to Parliament by the Secretary of State for Education, November 2010
It was nice to have a sunny and warm day in October to sit in the garden and do some reading. Looking at Chemistry World, I came across an article by Raychelle Burks (2021) on the the natural poison aconitine, extracted from plants collectively known as aconite. The article was punningly called 'The dead of aconite'.
Regular readers of this blog (if that is not a null set) may have noticed my interest in analogies used in teaching and communicating science, and so I was intrigued with the comparison between the effect of the poison and a damaged car engine:
Aconitine likely serves as a defensive tool for the plants that produce it, discouraging [!] predators with its deadly action. It acts quickly on sodium ion signalling channels, opening them and preventing their closure. 'To use a car analogy, if the valves in your car's engine open up, but then won't close, it's dead in the water', wrote toxicologist Justin Bower [sic]. 'Just like aconitine victims.'
Burks, 2021: 69
I was quite interested in following this up, but no citation was given. A little searching around the web led to the a blog called 'Nature's Poisons' written by forensic toxicologist Justin Brower [sic], and an entry on 'the queen of the poisons'.
Making the unfamiliar familiar
Analogy is just one technique used by teachers and others communicating technical or abstract ideas to assist in introducing those ideas – by suggesting that what is unfamiliar and is to be communicated is actually somewhat like something that the listeners(s) or reader(s) already know(s) about.
For this to work, the analogue needs to actually be more familiar than the target idea being communicated. Dr Brower's analogy relies upon people knowing enough about car engines to be familiar with the possibility of engine valves getting stuck open and preventing the car operating.
That the function and operation of the two systems are quite different means that knowing about car engines only offers limited support in learning about the effects of the poison on body cells, but this kind of superficial mapping between systems is true of many teaching analogies. Their role is more about initial familiarisation with the novel concept or phenomenon than providing a detailed explanation. We might almost see their primary role as affective rather than cognitive – making something quite technical seem less alien (and potentially less inaccessible).
Dr Brower explained in his blog that aconitine is found in the plant Monkshood (a.k.a. Wolfsbane), "in every part…from its pretty flowers right down to its dirty roots", and therefore
When any part of the plant is ingested, the aconitine is absorbed through the gut and goes to work. It binds to receptors that help regulate the muscle cells' sodium-ion channels, key components of the nervous system and cardiac cells (i.e. the heart). This action keeps the channels open, allowing sodium to flow freely into the cell. Unable to repolarize, the cells are stuck in a state of "open", and paralysis sets in. To use a car analogy, if the valves in your car's engine open up, but then won't close, it's dead in the water. Just like aconitine victims.
Brower, 2014
Cell membranes have to both prevent the unrestrained ingress and egress of materials, and yet also allow transport of particular substances across the barrier. Sodium ion channels are structures in the cell membrane that are specifically suited to allowing sodium ions (but not, say, calcium ions) to pass through. Moreover these channels do not remain open all the time. (They act as metaphorical 'gates' that can be closed.) The channels depend on specific proteins embedded in the membrane – substances that can have relatively 'large' molecules (that is, large for molecules!) with complex structures. The shapes of proteins can be very complicated.
Molecular shapes
The shapes of simple molecules are understood in terms of the electrical forces within the molecule (and at upper secondary school level the VSEPRT – the valance shell electron pair repulsion theory – model is often taught). Put very simply, the distribution of charges attracting and repelling each other (positive atomic cores, negative electrons) leads to the conformation of lowest potential energy.
The simple molecules can be considered to have one 'central' atomic centre (O in H2O; N in NH3; C in CH4; P in PCl5, and so forth) and the shape decided by considering the electronic distribution around that atom. In a molecule like propane (CH3CH2CH3) the shape can be considered by considering the situation around each of the of the C centres in turn, but taking into account that free rotation around the C-C bonds means that the molecule has a dynamic conformation. In larger molecules, there may be interactions (such as hydrogen bonding) between different parts of the molecule which influence and constrain the shape. Proteins may be very large molecules with many such interactions, often leading to a convoluted shape as the molecule 'folds' according to these interactions. Such protein folding can very difficult to predict.
Two views of a voltage-gated sodium channel. (Source: Protein Data Bank). The second view shows the protein located in the membrane (represented in grey).
VSEPRT is used to consider isolated molecules, and ignores the influence of other charges from outside the molecule (such as interactions with solvent molecules). The protein in a context such as a cell membrane may have quite a different shape than the same protein had it been isolated. Moreover, a change in the environment may affect the protein shape. In cells, when the membrane potential changes, the electric field around the ion channel proteins change, and they may change shape. The changes 'open' or 'close' the channels.
The same protein molecule, showing sites where two different toxins (shown as green and yellow) are known to bind and change the conformation of the structure preventing the 'gate' functioning. (Source: Protein Data Bank).
If a poison interferes with this process, the channels can no longer control the transport of sodium ions across the membrane in a way that enables the cell's normal functioning. Without this process nerve cells are unable to transmit electrical signals, and heart cells called myocytes (muscle cells) do not beat. That is important, as the beating of the heart is due to the synchronised beating of these cells. And the beating heart keeps the blood flowing, and with it the critical movement of substances (glucose, carbon dioxide, oxygen, etc.) around the body. Aconitine, then, acts as a cardiotoxin and neurotoxin (a heart poison and nerve poison).
Individual heart cells beat in this YouTube video from Wake Forest Baptist Medical Center's Institute for Regenerative Medicine
The car analogy breaks down in the sense that engine valves that are stuck open might later be closed again with some oil and a hammer and may then function again, and this restoration is not time critical; whereas after a heart has stopped beating, irreversible tissue damage will soon follow.
The first symptoms of aconitine poisoning appear approximately 20 min to 2 hr after oral intake and include paraesthesia [odd sensations], sweating and nausea. This leads to severe vomiting, colicky diarrhoea, intense pain and then paralysis of the skeletal muscles. Following the onset of life-threatening arrhythmia [irregular heartbeat], including ventricular tachycardia [fast, abnormal heartbeat] and ventricular fibrillation [loss of coordination in the muscle activity so there is no effective pumping1] death finally occurs as a result of respiratory paralysis or cardiac arrest.
In a worse case scenario for the car, the engine could be replaced, and the car made as good as new. Nonetheless, this is a useful analogy for anyone who knows a little of how the car engine works, as without working valves, the engine cycle (which I seem to recall summarised as 'suck-squeeze-bang-blow' on one course I once taught on) cannot occur, and the car goes nowhere.
cell does not function with channels unable to close
engine does not function with valves stuck open
if nerve and heart cells do not function, paralysis occurs, and person dies
if engine does not work, car does not go
negative mapping
tissue damage will soon be irreversible
valves may sometimes be freed up, restoring engine function – a quick response is not critical
Mapping between target idea and analogue
Work cited:
Beike, J., Frommherz, L., Wood, M., Brinkmann, B., & Köhler, H. (2004). Determination of aconitine in body fluids by LC-MS-MS. International Journal of Legal Medicine, 118(5), 289-293. doi:10.1007/s00414-004-0463-2
Brower, J. (2014). Aconitine: Queen of poisons. Nature's poisons. Retrieved from https://naturespoisons.com/2014/02/20/aconitine-queen-of-poisons-monkshood/
Burks, R. (2021). The dead of aconite. Chemistry World (October), 69.
Could an oral Covid-19 treatment be available soon?
There was an item on the BBC radio programme/podcast 'Science in Action' (23rd September 2021) about anti-viral agents being used in response to the COVID-19 pandemic: 'Could an oral Covid-19 treatment be available soon?'
"But even after someone is infected, the host actually mounts, for all these [respiratory] viruses, a really dramatic immune and inflammatory response. So it sort of lights a fire. And even when the virus stops replicating, you know that fire continues to burn, and in a lot of cases that's what lands people in the hospital. And so you want to prevent the virus from igniting that fire, that is what really ends up causing a huge amount of damage to the patient. …
the greatest benefit [of the antiviral drug being tested] is in the outpatient setting before that fire gets ignited."
Daria Hazuda being interviewed on 'Science in Action'
A scientific simile
Science communicators, such as teachers, but also scientists and journalists presenting science in the public media, often use techniques to 'make the unfamiliar familiar', to get across abstract or difficult ideas in ways that their audience can relate to.
These techniques can include analogies, metaphors and similes. Here Dr Hazuda used an analogy between the damage to tissue that can occur in disease, and the damage a fire can do. In particular, she was suggesting that the virus may be seen as like something which ignites a fire (such as a match or a spark) but which is not needed to keep the fire going once it had taken hold.
She introduced this idea by suggesting that the virus "sort of lights a fire". This can be considered a simile, which is a figure of speech which is a kind of explicit comparison where one thing is said to be like or similar to another.2 Dr Hazuda did not suggest that the virus actually lights a fire, but rather it has an effect which can be considered somewhat like ('sort of') igniting a fire.
"We didn't start the fire It was always burning, since the world's been turning We didn't start the fire No, we didn't light it, but we tried to fight it"
Billy Joel
Viruses triggering long term disease
The symptoms we experience when ill can be the results of our immune system reacting to illness, rather than the direct effect of the disease causing agent. That does not mean the disease itself would not harm us (infectious agents may be destroying cells which would not be obvious until extensive damage was done), but that in some conditions what we notice – perhaps sneezing, coughing, a raised temperature – is due to the immune response.
The immediate context of the Science in Action interview was the current COVID-19 pandemic caused by infection with the SARS-CoV-2 virus. However, the idea that a viral infection may trigger ('ignite') a longer term immune response (the 'fire') is not new with COVID. The syndrome sometimes known as chronic fatigue syndrome has unknown cause(s), but viruses are among the suspects. Viruses have been suspected as being a possible trigger (if perhaps in combination with other factors) in a range of autoimmune conditions. In autoimmune conditions the mechanisms that usually protect a person from infectious agents such as (some) bacteria and viruses attack and destroy the person's own cells leading to inflammation and potentially serious tissue damage.
People might commonly say that the immune system is 'meant' or 'intended' to protect us from diseases and that it sometimes 'goes wrong' leading to autoimmune disease – but strictly this is not a scientific way of thinking. The immune system has no purpose as such (this would be 'teleological' thinking), but has just evolved in ways such that it has on balance increased fitness.
From that perspective, it might not seem so strange that our immune systems are sometimes insufficient to protect us from harm, and yet can also sometimes be over-sensitive and start doing damage – as that surely is what we might expect if evolution has (through natural selection) led to a system which has tendedon the whole to be protective.
The admirable HLA-B27?
"HLA B27 plays an admirable, perhaps outstanding role in the immune response to viruses, however, it is also directly involved in the pathogenesis of the spondyloarthropathies"
Bowness, 2002: 866
My late wife Philippa was diagnosed with a complex autoimmune condition – she was told that she had atypical Wegener's granulomatosis (a disease now usually called Granulomatosis with polyangiitis2), a form of vasculitis (a disease leading to inflammation in the blood vessels), and that she might have been genetically susceptible to autoimmune diseases because she produced a particular type of human leukocyte antigen, HLA-B27. HLA is an important component of human immune systems, but the precise antigens a person produces varies, depending on their genes (just as we all have blood but people can be assigned into different blood groups). It was also suggested to her that an otherwise minor infection may have acted as a trigger in setting off the autoimmune problems.
Medicine today has some effective agents such as steroids that help 'dampen down' the 'fires' that damage tissues in autoimmune diseases. But these conditions can be very serious. Fifty years ago, most people found to have Wegener's granulomatosis were dead from that damage within a year of their diagnosis.
HLA-B27 is only found in a minority of people in most populations and is associated with a higher prevalence of certain immune conditions such as ankylosing spondylitis (an inflammatory condition especially affecting the spine), inflammatory bowel disease, and some forms of arthritis. It might seem odd that evolution has not led to the elimination of HGLA-B27 if it is associated with serious medical conditions. Yet, again, it may be that something which can make people prone to some conditions may also be better at protecting them from others.
People with HLA-B27 may be better at mounting an effective immune response to some viral infections (the fire is more readily ignited, we might say) and this might be enough of an advantage to balance its unfortunate role in autoimmune conditions. Over human history, HLA-B27 might have protected a great many people from dangerous infections, if also being responsible for a smaller number becoming very ill.
"HLA-B27 appears to excel at its natural function of binding and presenting viral peptide epitopes to cytotoxic T cells. We have suggested that HLA-B27 may, however, act as a 'double-edged sword'. Thus, certain features of its peptide binding ability or cell biology (perhaps those favouring excellent antiviral responses) might also lead to autoimmunity."
McMichael & Bowness, 2002: S157
That is, what makes this immune component so good at attacking certain viruses (as if the immune system had been doused in petrol so that the slightest spark might initiate a response) may also be responsible for its association with autoimmune diseases. HLA-B27 may (metaphorically) be the can of petrol that means that a viral spark starts not just a fire, but a conflagration.
1: "the first oral, direct-acting antiviral shown to be highly effective at reducing nasopharyngeal SARS-CoV-2 infectious virus" according to a preprint reported at medRχiv). A preprint is a paper written to report scientific research but NOT yet tested through peer review and formally published, and so treated as reporting more provisional and uncertain findings than a peer-reviewed paper.
2 By comparison, a metaphor may be considered an implicit comparison presented as if an identity: e.g., the nucleus is the brain of the cell.
2. The disease was named after the German physician Friedrich Wegener who described the condition. After Wegener was identified as a Nazi and likely war criminal (suspected, but not convicted) it was decided to rename the disease.
This was a very informative discussion of aspects of statistics, and one of the questions addressed was:
How often do false positive and false negative test results occur in medical screenings?
Screening for disease
Screening programmes test apparently healthy members of the population for serious medical issues in order to catch problems at an early stage when treatment offers the best prognosis.
Screening programmes can quickly test many people… (Image by Ahmad Ardity from Pixabay)
No tests are perfect, so tests will sometimes give misleading results – called false positives and false negatives.
a test result that is:
when an ideal perfect test would have shown positive
when an ideal perfect test would have shown negative
positive
is called a true positive
is called a false positive
negative
is called a false negative
is called a true negative
…but definitive diagnoses may require more sophisticated follow-up investigation (Image by Michal Jarmoluk from Pixabay)
Sometimes tests can be tuned to avoid many false negatives by tolerating a higher rate of false positive (or vice versa). This is similar to what happens in statistical hypothesis testing when the choice of 'confidence level' (the p {for probability} value used as a cut-off criterion for 'statistical significance') can be chosen according to whether it is more important to avoid false positives or to avoid false negatives.
Choice of confidence level reflects a balance between admitting false positives (due to chance events) and false negatives (where real effects are not distinguished from chance events). After, Taber, 2019, Fig. 7.
The notion of 'beyond reasonable doubt' used in criminal trials can be understood as based on the principle that it is better that some guilty perpetrators are not convicted at trial than to risk miscarriages of justice where innocent people may lose their liberty (or indeed in some jurisdictions, perhaps their lives). That is, it is better to have false negatives than false positives in criminal convictions.
In medical screening programmes, it is common to have an initial test which might give quite a few positive results (but hopefully not produce many false negatives, where a person with a disease appears to be clear according to the test), even though most of the positive results will prove to be false alarms (false positives) when followed up by a more sophisticated test that it is impractical or too expensive to use for mass screening.
The bias towards false positives built into some medical screening trials means that a person should not be too despondent at getting a positive result in the initial screen. Dr Yates worked through one example to show that based on the rates of false positives on certain screening tests, a person called for regular screenings over a number of years was actually more likely than not to get at least one positive screening result – but still unlikely to be unlucky enough to have the disease.
A teaching analogy
What I most liked was the use of an analogy to compare the logic of the screening process with a familiar everyday situation. Teaching can be seen as a process of making the unfamiliar familiar, and teachers often do this by comparing the unfamiliar they are charged with teaching about with something already familiar to the their students. That is only a starting point for supporting a developing understanding of the new concept or phenomenon, but it often is very useful in making abstract new ideas seem less threatening or inaccessible.
One common way of making the unfamiliar familiar is through analogy: showing that what is new has a familiar conceptual structure – mapping onto a set of ideas already understood.
Scientists charged with giving talks to a public audience as part of 'public communication' of science ('outreach') or attempts to improve 'public understanding' of science also have the job of making the unfamiliar familiar and may also use teaching analogies – as Dr Yates did here:
"I would make the analogy to screenings with a job interview. So, when a company wants to hire someone for a job, they send out an advert, and people send in their c.v.s. And the company can read those c.v.s quickly and make a shortlist. And that's a really cheap way, just as the first screen is a really cheap way of identifying people, who might be suitable for the job, people who might have breast cancer. And then for the job interview you call people in and you interview them and you throw 'assessment centres' at them, you do tests which are too expensive to do to the whole population at large to identify someone good for the job, but you can do it to this smaller population. And in the same way, with the screen we invite people in and we throw more expensive, more accurate tests at them to give them a diagnosis. And the point is, just because you would get invited to an interview for a job you had applied for, you wouldn't assume that you had got the job, right? So, in the same way, just because you get invited for further tests after a screen, you shouldn't assume you have the disease that is being screened for. You should wait and go to the follow-up test and see what that follow-up test says."
Dr Kit Yates explaining the logic of screening programmes
Based on an analogy used by Dr Kit Yates
This seemed a well-considered analogue, one that would be very accessible to most people in the audience. It is a common experience to have applied for jobs: perhaps sometimes not being shortlisted; sometimes called in for interview but not appointed; and sometimes being offered the job. 2
The explanations flowed nicely between the target concept (screening) and the analogue (shortlisting) – as can be seen in the tabulated version below.
"I would make the analogy to screenings
with a job interview.
So, when a company wants to hire someone for a job, they send out an advert, and people send in their c.v.s.
And the company can read those c.v.s quickly and make a shortlist.
And that's a really cheap way,
just as the first screen is a really cheap way of identifying people,
who might be suitable for the job,
people who might have breast cancer.
And then for the job interview you call people in and you interview them and you throw 'assessment centres' at them, you do tests which are too expensive to do to the whole population at large to identify someone good for the job, but you can do it to this smaller population.
And in the same way, with the screen we invite people in and we throw more expensive, more accurate tests at them to give them a diagnosis.
And the point is, just because you would get invited to an interview for a job you had applied for, you wouldn't assume that you had got the job, right?
So, in the same way, just because you get invited for further tests after a screen, you shouldn't assume you have the disease that is being screened for.
You should wait and go to the follow-up test and see what that follow-up test says."
An effective teaching analogy needs to have an analogue that is sufficiently familiar for an audience to appreciate its conceptual structure – and that structure must fit well when mapped across to the target concept. 'Medical screening is like job shortlisting' seems to work well on both these criteria.
1: "If you see a newspaper headline with a big, bold statistic, how do you know that you can trust it? How often do false positive and false negative test results occur in medical screenings? And how do you safely bet whether or not 2 people in any room will share a birthday? This month we hear from Kit Yates about the maths of medicine, crime and the media, exploring real-world data from his book, 'The Maths of Life and Death'. This talk was recorded from our theatre at the Royal Institution, on 21 January 2020." https://soundcloud.com/royal-institution/maths-trust
2. It might be suggested that this process reflects a middle class /professional/white collar employment experiences, whereas for many jobs, such as much shop or factory work, an employer is likely to employ the first apparently suitable candidate that applies, rather than using a slower and more expensive two stage process. This is so, but the situation of short-listing is still generally familiar through story lines in fiction, such as in television dramas.
Bee-ware chemicals! (Images by PollyDot and Clker-Free-Vector-Images from Pixabay)
A recent episode of the BBC Inside science radio programme and podcast was entitled 'Bees and multiple pesticide exposure'. This discussed a very important issue that I have no wish to make light of. Researchers were looking at the stressors which might be harming honey bees, very important pollinators for many plants, and concluded that these likely act synergistically. That is a colony suffering from, say a drought and at the same time a mite infection, will show more damage that one would expect from simply adding the typical harm of each as if independent effects. Rather there are interactions.
This is hardly surprising, but is none-the-less a worrying finding.
Bees and multiple pesticide exposure episode of BBC Inside Science
However, my 'science teacher' radar honed in on an aspect of the language used to explain the research. The researcher interviewed was Dr Harry Siviter of the University of Texas at Austin. As part of his presentation he suggested that…
"Exposure to multiple pesticides is the norm, not the exception. So, for example a study in North America showed that the average number of chemicals found in a honey bee colony is six, with a high of 42. So, we know that bees are exposed to multiple chemicals…"
The phrase that stood out for me was "the average number of chemicals found in a honey bee colony is six" as clearly that did not make any sense scientifically. At least, not if the term 'chemical' was meant to refer to 'chemical substance'. I cannot claim to know just how many different substances would be found if one analysed honey bee colonies, but I am pretty confident the average would be orders of magnitude greater than six. An organism such as a bee (leaving aside for a moment the hive in which it lives) will be, chemically, 'made up' of a great many different proteins, amino acids, lipids, sugars, nuclei acids, and so forth.
"the average number of chemicals found in a honey bee colony is six"
From the context, I understood that Dr Siviter was not really talking about chemicals in general, but pesticides. So, I am (not for the first time) being a pedant in pointing out that technically he was wrong to suggest "the average number of chemicals found in a honey bee colony is six" as any suitably informed listener would have immediately, and unproblematically, understood what he meant by 'chemicals' in this context.
Yet, as a teacher, my instinct is to consider that programmes such as this, designed to inform the public about science, are not only heard by those who are already well-versed in the sciences. By its nature, BBC Inside Science is intended to engage with a broad audience, and has a role in educating the public about science. I also knew that this particular pedantic point linked to a genuine issue in science teaching.
A common alternative conception
The term chemical is not usually used in science discourse as such, but rather the term substance. Chemical substances are ubiquitous, although in most everyday contexts we do not come across many pure samples of single substances. Tap water is nearly all water, and table salt is usually about 99% sodium chloride, and sometimes metals such as copper or aluminium are used in more or less pure form. But these tend to be exceptions – most material entities we engage with are not pure substances ('chemicals'), rather being mixtures or even more complex (e.g., wood or carrot or hair).
In everyday life, the term chemical tends to be used more loosely – so, for example, household bleach may be considered 'a chemical'. More problematically 'chemicals' tends to be seen as hazardous, and often even poisonous. So, people object to there being 'chemicals' in their food – when of course their food comprises chemicals and we eat food to access those chemicals because we are also made up of a great many chemicals. Food with the chemicals removed is not food, or indeed, anything at all!
In everyday discourse 'chemical' is often associated with 'dangerous' (Image by Arek Socha from Pixabay)
So, science teachers not only have the problem that in everyday discourse the term 'chemical' does not map unproblematically on 'substance' (as it is often used also for mixtures), but even more seriously that chemicals are assumed to be bad, harmful, undesirable – something to be avoided and excluded. By contrast, the scientific perspective is that whilst some chemicals are potentially very harmful, others are essential for life. Therefore, it is unhelpful when science communicators (whether journalists, or scientists themselves) use the term 'chemical' to refer only to potentially undesirable chemicals (which even then tend to be undesirable only in certain contexts), such as pesticides which are found in, and may harm, pollinators.
I decided to dig into the background of the item.
The news item
I found a news item in 'the Conversation' that discuses the work.
Dr Siviter's Article in the Conversation
It began
"A doctor will always ask if you are on any other medication before they write you a prescription. This is because pharmaceuticals can interact with each other and potentially disrupt the treatment, or even harm the patient. But when agrochemicals, such as pesticides, are licensed for use on farms, little attention is paid to how they interact with one another, and so their environmental impact is underestimated."
Siviter, 2021
This seemed a very good point, made with an analogy that seemed very telling.
"We analysed data gathered in scientific studies from the last two decades and found that when bees are exposed to a combination of pesticides, parasites and poor nutrition, the negative impact of each is exacerbated. We say that the cumulative effect of all these things is synergistic, meaning that the number of bees that are killed is more than we would predict if the negative effects were merely added together."
Siviter, 2021
This seems important work, and raises an issue we should be concerned about. The language used here was subtly different from in the radio programme:
"Many agrochemicals, such as neonicotinoids, are systemic, meaning they accumulate in the environment over several months, and in some cases years. It is perhaps not surprising then that honeybee colonies across the US have on average six different agrochemicals present in their wax, with one hive contaminated with 39 [sic, not 42]. It's not just honeybees which are at risk, though: wild bees such as bumblebees are also routinely exposed."
Siviter, 2021
So, here it was not 'chemicals' that were being counted but 'agrochemicals' (and the average figure of 6 now referred not to the colony as a whole, but only to the beeswax.)
The meta-analysis
'Agrochemicals' was also the term used in the research paper in the prestigious journal Naturewhere the research had been first reported,
"we conducted a meta-analysis of 356 interaction effect sizes from 90 studies in which bees were exposed to combinations of agrochemicals, nutritional stressors and/or parasites."
Siviter, et al., 2021
A meta-analysis is a type of secondary research study which collects results form a range of related published studies and seeks to identify overall patterns.
The original research
Moreover, the primary study being referred to as the source of the dubious statistic (i.e., that "the average number of chemicals found in a honey bee colony is six") referred not to 'chemicals' but to "pesticides and metabolites" (that is, substances which would be produced as the bee's metabolism broke the pesticides down):
"We have found 121 different pesticides and metabolites within 887 wax, pollen, bee and associated hive samples….
Almost all comb and foundation wax samples (98%) were contaminated with up to 204 and 94 ppm [parts per million], respectively, of fluvalinate and coumaphos, and lower amounts of amitraz degradates and chlorothalonil, with an average of 6 pesticide detections per sample and a high of 39."
Mullin, et al., 2010
Translation and representation
Scientific research is reported in research journals primarily for the benefit of other researchers in the field, and so is formatted and framed accordingly – and this is reflected in the language used in primary sources.
A model of the flow of scientific to public knowledge (after McInerney et al., 2004)
It is important that science which impacts on us all, and is often funded from public funds, is accessible to the public. Science journalism, is an important conduit for the communication of science, and for his to be effective it has to be composed with non-experts in the public in mind.
It is perfectly sensible and desirable for a scientist engaging with a public audience to moderate technical language to make the account of research more accessible for a non-specialist audience. This kind of simplification is also a core process in developing science curriculum and teaching.
However, in the case of 'chemical' I would suggest scientists take care with using the term (and avoid it if possible), as science teachers commonly have to persuade students that chemicals are all around of us, are not always bad for us, are part of us, and are essential. That pesticides and their breakdown products have been so widely detected in bee colonies is a matter of concern, as pesticides are substances that are used because of their detrimental effects on many insects and other organisms that might damage crops.
Whilst that is science deserving public attention, there are a good many more than 6 chemicals in any bee colony, and – indeed – we would want most of them to be there.
References:
McInerney, C., Bird, N., & Nucci, M. (2004). The Flow of Scientific Knowledge from Lab to the Lay Public: The Case of Genetically Modified Food. Science Communication, 26(1), 44-74. doi:10.1177/1075547004267024 https://journals.sagepub.com/doi/10.1177/1075547004267024
Mullin, C. A., Frazier, M., Frazier, J. L., Ashcraft, S., Simonds, R., vanEngelsdorp, D., & Pettis, J. S. (2010). High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health. 5(3): e9754. PLoS ONE, 5(3), e9754. doi:10.1371/journal.pone.0009754 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0009754
Siviter, H., Bailes, E. J., Martin, C. D., Oliver, T. R., Koricheva, J., Leadbeater, E., & Brown, M. J. F. (2021). Agrochemicals interact synergistically to increase bee mortality. Nature. doi:10.1038/s41586-021-03787-7 https://www.nature.com/articles/s41586-021-03787-7
Imagine the banks were contracted to deliver school teaching…employing their digital assistants
Keith S. Taber
The teacher of the future – imagine the government invited bids to 'deliver' schooling most cost-effectively (only a matter of time?), and the banks undercut schools by proposing to use their existing intelligent technology. Image by Gerd Altmann from Pixabay
Hi, I'm Rubis, your intelligent science teaching system. I can help with all sorts of everyday science learning queries. Let me know how I can help you today, or try asking me a short, simple question, such as "what is the formula of water?" and I'll be able to help.
Rubis, why is mercury a liquid at room temperature?
I didn't quite catch that, but I'm learning all the time.
Here are some of the top things that I get asked.
What are the three states of matter? Why are mushrooms not considered plants? What comes between gamma rays and ultraviolet radiation in the electromagnetic spectrum? Who invented gravity? Who was Archimedes' principal?
Rubis, why is mercury a liquid at room temperature?
One moment please, I'm just typing. Please select an option:
The periodic table The respiratory system Electrical resistance Acids Food webs
I'm trying to find out why mercury is a liquid at room temperature?
Just to check, do you mean:
What is the difference between a moon and a comet? How dangerous is ascorbic acid? Why is love like oxygen? 1 How can an acrobat balance on a trapezoid of forces? When did retroviruses come back into vogue? None of these
None of these
I can help with all sorts of everyday science learning queries. Try asking me a short, simple question, such as "what are the three ways in which heating occurs" and I'll be able to help.
…
Science teaching, of course, is a process that requires a well-prepared, highly knowledgeable, teacher who is sensitive to, and responsive to, individual learners whose moods and motivations shift from day to day and who may at any time ask a question that the teacher would never have predicted in advance. That's part of the joy (and challenge) of teaching, which when done well is an interactive process where the teacher has to make myriad real-time, 'on-line', decisions in response to a complex and ever changing context. That is, it requires a good deal of 'intelligence'.
Machine intelligence?
One (questionable) sign of 'progress' in our increasingly digital society is how getting access to costumer service usually involves perusing 'contact us' webpages that are designed to send you initially to fixed pages with answers to to 'FAQs' (frequently asked questions); only then offering 'chat' with an 'intelligent' assistant – which seems programmed to only pass you on to a human once it has recognised you have been sent round the same flow-chart loop more than once.
As I have pointed out before, this would be fine if these 'chat-bots' were actually intelligent (even in the limited sense of a learning machine).
My faux 'dialogue' above may seem an unfair parody. (Not a genuine dialogue of course as there was no meeting of minds and taking on board of the other's perspective.)
But if my bank (RBS) were to be given a contract to provide digital teaching services, I imagine it would be just like that. If they could do better, then surely their chat-bot for bank customers would be more useful and less frustrating.
The bank initiated the conversation…
My bank sent me an email suggesting that I would soon no longer be able to make on-line purchases with my debit card unless I used a mobile 'phone (which currently I do not, and am not planning to anytime soon). "As part of new regulations, we'll often ask you to confirm that it's really you who's making the purchase when you use your card to pay for something online. To do this, you'll need to enter a six-digit one-time passcode (OTP) that we'll send to your mobile phone." Of course the message also told me "Please do not reply to this email as the address is not monitored". Hm, so how do I get in touch…
Cora offers "support" and "an instant answer"
Cora, the chat-bot, could make no sense of my inquiry.
Of course no chat-bot (or teacher) could be expected to always respond to any random enquiry. When I was teaching I would not have been able to instantly answer a question from outside my teaching subjects…
"Sir, in what year did Hannibal Lecter cross the Alps with Elephants?" 2
Here, however, I was not raising some obscure topic that the Bank could not have anticipated, as I was RESPONDING to a conversation initiated by the Bank!
Connected with Cora
Perhaps I am being unreasonable?
Hey there. I'm Cora, your digital assistant. Let me know how I can help you today, or select one of the top questions that I am being asked:
Please select an option:
Close an account Change my details Order paying in book Cancel transaction
Cora – 12:00
I choose to let 'her' know how she can help me today:
I have just had an email from the bank, suggesting in future I will need a mobile phone to make online purchases. At the present time I have no need for nor intention of getting a mobile phone.
Keith
I didn't quite catch that, but I'm learning all the time.
Here are some of the top things that I get asked.
Please select an option:
Coronavirus support Unknown transaction Cancel transaction Pending transaction Change account details Make a payment
More
Cora – 12:01
More
selected
One moment please, I'm just typing.
Please select an option:
Check a statement Help logging in Paying in a cheque Struggling financially Check account info Refunds/Retail disputes None of the above
Cora – 12:02
None of the above
selected
I can help with all sorts of everyday banking queries. Try asking me a short, simple question, such as "how do I order a new card?" and I'll be able to help.
Cora – 12:02
I have just had an email from the bank, suggesting in future I will need a mobile phone to make online purchases. At the present time I have no need for nor intention of getting a mobile phone. Please explain how I should proceed.
Keith
Please select an option:
Just to check, do you mean:
Benefit Insurance Claim Manage receipts in app Check my eligibility Suspicious email Remove an account holder None of these
Cora – 12.03
Just to check?
None of these
selected
I didn't quite catch that, but I'm learning all the time.
Here are some of the top things that I get asked.
Please select an option:
Coronavirus support Unknown transaction Cancel transaction Pending transaction Change account details Make a payment
more
Cora – 12.03
more
selected
Please select an option:
Check a statement Help logging in Paying in a cheque Struggling financially Check account info Refunds/Retail disputes None of the above
Cora -12.03
None of the above
Selected
I can help with all sorts of everyday banking queries. Try asking me a short, simple question, such as "how do I order a new card?" and I'll be able to help.
Cora – 12:03
So, basically, Cora can help me as long as I ask a question she has specifically prepared for. I may as well have asked her how come a metal like mercury could be a liquid at room temperature.
Just imagine teachers behaved like that!
Original image by 14995841 from Pixabay
Footnotes:
1 apparently because if you get too much you will get too 'high', but if you do not get enough you will die
"Love is like oxygen You get too much, you get too high Not enough and you're gonna die Love gets you high"
2 This suggests a science joke:
What was the outcome when Hannibal crossed the alps with elephants?
I am not sure, but the offspring would have been infertile.
A faecal transplant is like wild flower seeds in some soil
Keith S. Taber
"Many animals naturally ate each other's poo…as a way of staying healthy" Prof. Tim Spector. (Original image by Debbie De Jager from Pixabay, with apologies to Monty Python)
I was listening to a podcast from 'Science Stories' (BBC Radio 4) about 'Lady Mary Montagu's Smallpox Experiment', where Naomi Alderman described how the aforementioned Lady Mary Wortley Montagu brought the practice of opening veins to introduce some smallpox into the body, as a way of protecting against the deadly disease, back from Turkey to Britain.
This was compared with the process of faecal transplantation which was apparently first used in China, and is increasingly being seen as a valuable treatment for some gut disorders. This is the process of ingesting, under carefully controlled conditions, some human faeces – either some of your own carefully preserved (for example, some cancer patients have a sample collected and stored before starting chemotherapy), or from some donor who is willing to offer some of their own. Unlike some other donor procedures (such as kidney donation) this is non-invasive and concerns material most of us just dispose of anyway!
Tim Spector, Professor of Genetic Epidemiology at Kings College, London explained the significance of the gut microbiome, the community of something like 100 trillion microbes that typically occupy a human gut. The importance of these organisms for human health is increasingly being appreciated.
Treating Clostridium difficile infection
Disturbances of the gut microbiome can lead to ill health. One particular example is the condition known as Clostridium difficile infection ('C. diff') – which is commonly experienced in hospitals when patients have extensive courses of antiobiotics – which can sadly kill the useful gut microbes as well those disease-causing organisms being targeted. Clostridium difficile (being itself unaffected by many commonly used antibiotics) can in these circumstances reproduce rapidly and vastly increase its numbers. This is problematic as the organism releases a toxin.
C. diff infection can lead to the sufferer needing to visit the toilet urgently and repeatedly – many times each day. This is not only undesirable in itself, but interferes with getting nutrition from food (if the person has any appetite to eat), and leads to dangerous dehydration – and can have other complications. So, this is a very serious condition, and it is readily transmitted from one person to another.
"C. difficile is an infectious Gram-positive spore-forming bacillus microorganism of the gastrointestinal tract, and its toxin expression causes gastrointestinal illness with a wide spectrum of severity, ranging from mild diarrhea to pseudomembranous colitis, toxic megacolon, sepsis-like picture and death…"
Bien, Palagan & Bozko, 2013: 53
Many people have a low level of Clostridium difficile specimens in their gut normally, but as one small part of the much larger and diverse population of gut microbes – in which context they cause no problems.
"C. difficile does not cause any significant disease when it is present in small numbers. However, disturbance of the normal intestinal flora (dysbiosis) by several potential causative factors may result in unlimited [sic] expansion of C. difficile in the microbiota, leading to inflammation and damage of the gut mucosa…"
Bien, Palagan & Bozko, 2013: 56
Someone who has suffered from C. diff infection needs a way to repopulate their gut with a good range of the usual different microbes. And that is when consuming a sample of a healthy person's excrement can be useful. (This is of course done under medical direction and supervision, both to maintain hygiene and to ensure the donor does not have medical conditions that might be passed on with the sample.)
A teaching analogy for faecal transplantation
This was all explained by Prof. Spector using an analogy.
Analogies are comparisons where a less familiar, and perhaps abstract or counterintuitive, concept is explained in terms of something familiar that can be seen to have a similar conceptual structure (see the figure). Analogies are commonly used in science teaching and public communication of science (as here in a radio programme) to introduce scientific ideas.
Figure: A teaching analogy to explain why faecal transplantation can be used to treat C. diff (based on the presentation by Prof. Tim Spector in 'Lady Mary Montagu's Smallpox Experiment')
How does your garden grow?
Prof. Spector developed a comparison between the different microbes found in the gut, and the plants growing in a garden:
"These nasty infections are the most extreme, if you like, that pretty much wipe out most of our normal species. So … we might, say, start with a thousand species and people [with C. diff] might be down to just ten or so, different ones and so nasty ones take over. It's a bit like a garden that has gone very badly wrong and you have put too much herbicide all over it and it looks like an Arizona back yard with a few burning tyres in it. It's very easy for things to take over that and what we want to get, is by putting these bugs in there, to create a really healthy garden that gets back to normal that looks like a nice English country garden with lots of blooms, and really good soil, and lots of plants interacting with each other, and that's the way to think about these microbes, but to do that, to get to this nice rosy picture of a country garden you have to go through yucky stages first"
Before and after faecal transplantation: a medical treatment that can transform your 'garden'? (Images by Simon (left) and Prawny (right) from Pixabay) [Move the slider to change between the pictures].
So the idea of taking a sample of someone else's excrement into our own gut may seem "yukky" – and is definitely NOT recommended without proper procedures and supervision – but may sometimes be a sensible and beneficial medical treatment. Just think of it as resewing the garden of the gut with a nice selection of seeds that will give rise to a diverse selection of colourful blooms.
Naomi Alderman: Instead of poo, we could think to ourselves, 'wild flower seeds'
Tim Spector: It's wild flower seeds with a bit of soil in it as well, so they have come in their own pot [sic] if you like.
'wild flower seeds with a bit of soil…in their own pot'? (Images by OpenClipart-Vectors from Pixabay)
Work cited:
Bien, J., Palagani, V., & Bozko, P. (2013). The intestinal microbiota dysbiosis and Clostridium difficile infection: is there a relationship with inflammatory bowel disease? Therapeutic advances in gastroenterology, 6(1), 53-68. doi:10.1177/1756283X12454590 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3539291/
As part of the primary scientific literature, it publishes articles written by specialist scientists in a technical language intended to be understood by other specialists. Dense scientific terminology is not used to deliberately exclude general readers (as sometimes suggested), but is necessary for scientists to make a convincing case for new knowledge claims that seem persuasive to other specialists. This requires being precise, using unambiguous technical language."The thingamajig kind of, er, attaches to the erm, floppy bit, sort of" would not do the job.
Science News however is news media – it publishes journalism (indeed, 'since 1921' the site reports – although that's the publication and not its website of course.) While science journalism is not essential to the internal processes of science (which rely on researchers engaging with each other's work though scholarly critique and dialogue) it is very important for the public's engagement with science, and for the accountability of researchers to the wider community.
Science journalists have a job similar to science teachers – to communicate abstract ideas in a way that makes sense to their audience. So, they need to interpret research and explain it in ways that non-specialists can understand.
The news article told me
"Like a shaggy dog in springtime, some black holes have to shed… Unlike dogs with their varied fur coats, isolated black holes are mostly identical. They are characterized by only their mass, spin and electric charge. According to a rule known as the no-hair theorem, any other distinguishing characteristics, or "hair," are quickly cast off. That includes magnetic fields."
Conover, 2013
Here there is clearly the use of an analogy – as a black hole is not the kind of thing that has actual hair. This would seem to be an example of a journalist creating an analogy (just as a science teacher would) to help 'make the unfamiliar familiar' to her readers:
just as
dogs with lots of hair need to shed some ready for the warmer weather (a reference to a familiar everyday situation)
so, too, do
black holes (no so familiar to most people) need to lose their hair…
Surely a better analogy would be along the lines that just as dogs with lots of hair need to shed some ready for the warmer weather, so to do black holes need to lose their magnetic fields…
An analogy is used to show a novel conceptual structure (here, relating to magnetic fields around black holes) maps onto a more familiar, or more readily appreciated, one (here, that a shaggy dog will shed some of its fur). A teaching analogy may not reflect a deep parallel between two systems, as its function may be just to introduce an abstract principle.
Conover did not invent the 'hair' reference for her ScienceNews piece – rather she built her analogy on a term used by the scientists themselves. Indeed, the title of the cited research journal article was "Magnetic Hair and Reconnection in Black Hole Magnetospheres", and it was a study exploring the consequences of the "no-hair theorem" – as the authors explained in their abstract:
"The no-hair theorem of general relativity states that isolated black holes are characterized [completely described] by three parameters: mass, spin, and charge."
Bransgrove, Ripperda & Philippov, 2021
However, some black holes "are born with magnetic fields" or may "acquire magnetic flux later in life", in which case the fields will vary between black holes (giving an additional parameter for distinguishing them). The theory suggests that these black holes should somehow lose any such field: that is, "The fate of the magnetic flux (hair) on the event horizon should be in accordance with the no-hair theorem of general relativity" (Bransgrove, Ripperda & Philippov, 2021: 1). There would have to be a mechanism by which this occurs (as energy will be conserved, even when dealing with black holes).
So, the study was designed to explore whether such black holes would indeed lose their 'hair'. Despite the use of this accessible comparison (magnetic flux as 'hair'), the text of the paper is pretty heavy going for someone not familiar with that area of science:
"stationary, asymptotically flat BH spacetimes…multipole component l of a magnetic field…self-regulated plasma…electron-positron discharges…nonzero stress-energy tensor…instability…plasmoids…reconnection layer…relativistic velocities…highly magnetized collisionless plasma…Lundquist number regime…Kerr-schild coordinates…dimensionless BH spin…ergosphere volume…spatial hypersurfaces…[…and so it continues]"
(Bransgrove, Ripperda & Philippov, 2021: 1).
"Come on Harry, you know full well that 'the characteristic minimum plasma density required to support the rotating magnetosphere is the Goldreich-Julian number density' [Bransgrove, Ripperda & Philippov, 2021: 2], so hand me that hyperspanner." Image from Star Trek: Voyager (Paramount Pictures)
Spoiler alert
I do not think I will spoil anything by revealing that Bransgrove and colleague conclude from their work that "the no-hair theorem holds": that there is a 'balding process' – the magnetic field decays ("all components of the stress-energy tensor decay exponentially in time"). If any one reading this is wondering how they did this work, given that most laboratory stores do not keep black holes in stock to issue to researchers on request, it is worth noting the study was based on a computer simulation.
That may seem to be rather underwhelming as the researchers are just reporting what happens in a computer model, but a lot of cutting-edge science is done that way. Moreover, their simulations produced predictions of how the collapsing magnetic fields of real black holes might actually be detected in terms of the kinds of radiation that should be produced.
As the news item explained matters:
Magnetic reconnection in balding black holes could spew X-rays that astronomers could detect. So scientists may one day glimpse a black hole losing its hair.
Conover, 2013
So, we have hairy black holes that go through a balding process when they lose their hair – which can be tested in principle because they will be spewing radiation.
Balding is to hair, as…
Here we have an example of an analogy for a scientific concept. Analogies compare one phenomenon or concept to another which is considered to have some structural similarity (as in the figure above). When used in teaching and science communication such analogies offer one way to make the unfamiliar familiar, by showing how the unfamiliar system maps in some sense onto a more familiar one.
hair = magnetic field
balding = shedding the magnetic field
Black holes are expected to be, or at least to become, 'hairless' – so without having magnetic fields detectable from outside the event horizon (the 'surface' connecting points beyond which everything, even light, is unable to 'escape' the gravitational field and leave the black hole). If black holes are formed with, or acquire, such magnetic fields, then there is expected to be a 'balding' process. This study explored how this might work in certain types of (simulated) black holes – as magnetic field lines (that initially cross the event horizon) break apart and reconnect. (Note that in this description the magnetic field lines – imaginary lines invented by Michael Faraday as a mental tool to think about and visualise magnetic fields – are treated as though they are real objects!)
Some such comparisons are deliberately intended to help scientists explain their ideas to the public – but scientists also use such tactics to communicate to each other (sometimes in frivolous or humorous ways) and in these cases such expressions may do useful work as short-hand expressions.
So, in this context hair denotes anything that can be detected and measured from outside a black hole apart form its mass, spin, and charge (see, it is much easier to say 'hair')- such as magnetic flux density if there is a magnetic field emerging from the black hole.
A dead metaphor?
In the research paper, Bransgrove, Ripperda and Philippov do not use the 'hair' comparison as an analogy to explain ideas about black holes. Rather they take the already well-established no-hair theorem as given background to their study ("The original no-hair conjecture states that…"), and simply explain their work in relation to it ("The fate of the magnetic flux (hair) on the event horizon should be in accordance with the no-hair theorem of general relativity.")
Whereas an analogy uses an explicit comparison (this is like that because…), a comparison that is not explained is best seen as a metaphor. A metaphor has 'hidden meaning'. Unlike in an analogy, the meaning is only implied.
"The no-hair theorem of general relativity states that isolated black holes are characterized by three parameters: mass, spin, and charge";
"The original no-hair conjecture states that all stationary, asymptotically flat BH [black hole] spacetimes should be completely described by the mass, angular momentum, and electric charge"
Bransgrove and colleagues do not need to explain why they use the term 'hair' in their research report as in their community it has become an accepted expression where researchers already know what it is intended to mean. We might consider it a dead metaphor, an expression which was originally used to imply meaning through some kind of comparison, but which through habitual use has taken on literal meaning.
Science has lots of these dead metaphors – terms like electrical charge and electron spin have with repeated use over time earned their meanings without now needing recourse to their origins as metaphors. This can cause confusion as, for example, a learner may develop alternative conceptions about electron spin if they do not appreciate its origin as a metaphor, and assumes an electron spins in the same sense as as spinning top or the earth in space. Then there is an associative learning impediment as the learner assumes an electron is spinning on its axis because of the learner's (perfectly reasonable) associations for the word 'spin'.
The journalist or 'science writer' (such as Emily Conover), however, is writing for a non-specialist readership, so does need to explain the 'hair' reference. So, I would characterise the same use of the terms hair/no-hair and balding as comprising a science analogy in the news item, but a dead metaphor in the context of the research paper. The meaning of language, after all, is in the mind of the reader.
Is the work of cognition like the work of a palaeontologist? (Image by Brenda Geisse from Pixabay)
I like the reflexive nature of this account – of someone reconstructing an analogy
abouthow cognition reconstructs coherent wholes from partial, fragmented data
froma partial, fragmented memory representation.
I was reading something about memory function that piqued my interest in an analogy:
"Neisser, using an analogy initially developed by Hebb (1949) to characterize [sic] perception, likened the rememberer to a paleontologist who attempts to reconstruct a dinosaur from fragmentary remains: 'out of a few stored bone chips, we remember a dinosaur'…"
Schacter, 1995, p.10
I was interested enough to look up the original use of this analogy (as I report below).
This links to three things that have separately interested me:
the nature of memory
the constructivist account of learning and cognition
using analogies in teaching and comunicating science
The nature of our memories
I have long been interested in what memory is and how it works – and its role in academic learning (Taber, 2003). In part this perhaps derives from the limits of my own memory – I have been reasonably successful academically, but have never felt I had a good memory (and I seem to get more 'absent minded' all the time). This interest grew as it became clearer to me that our memory experiences seem to be quite different – my late wife Philippa would automatically and effortlessly remember things in a way that that seemed to me to be a kind of superpower. (She was once genuinely surprised that I could not picture what a family member had been wearing on arriving at a family event years before, whereas I thought I was doing pretty well to even remember I had been there.) Now that neurodiversity is widely recognised, it seems less surprising that we do not all experience memory in the same way.
A lot of people, however, understand memory in terms of a kind of folk-model (that is, a popular everyday account which does not match current scientific understanding) – along the lines that we put information into a memory store, where – unless it gets lost and we forget – we can later access it and so remember what it was that we committed to memory. Despite the ubiquity of that notion, research suggests that is not really how memory functions. We might say that this is a common alternative conception of how memory works.
Schacter was referring back to a tradition that began a century ago when Bartlett carried out a series of studies on memory. Bartlett (1932/1995) would, for example, expose people to a story that was unfamiliar to his study participants, and then later ask them to retell as much of the story as they could remember. As might be expected, some people remembered more details than others.
What perhaps was less predictable at the time was the extent to which people included in their retelling details that had not been part of the original story at all. These people were not deliberately embellishing or knowingly guessing, but reporting, as best they could, what their memory suggested had been part of the original story.
People who habitually exhibit this 'confabulation' to an pathological degree (perhaps remembering totally fantastic things that clearly could not be true) are recognised as having some kind of problem, but it transpires this is just an extreme of something that is normal behavior. Remembering is not the 'pulling something out of storage' that we may experience it as – as actually what we remember is more like a best guess based on insufficient data (but a guess made preconsciously, so it appears in our conscious minds as definitive) than a pristine copy of an original experience. Memory is often more a matter of constructing an account from the materials at hand than simply reading it out from something stored.
Thus the analogy. Here is some wider context for the quote presented above:
"The publication of Neisser's (1967) important monograph on cognitive psychology rekindled interest in Bartlett's ideas about schemas and reconstructive memory. According to Neisser, remembering the past is not a simple matter of reawakening a dormant engram or memory trace; past events are constructed by using preexisting knowledge and [schemata] to piece together whatever fragmentary remains of the initial episode are available in memory. Neisser, using an analogy initially developed by Hebb (1949) to characterize [sic] perception, likened the rememberer to a paleontologist who attempts to reconstruct a dinosaur from fragmentary remains: 'out of a few stored bone chips, we remember a dinosaur' (1967, p.285). In this view, all memories are constructions because they include general knowledge that was not part of a specific event, but is necessary to reconstruct it. The fundamentally constructive nature of memory in turn makes it susceptible to various kinds of distortions and inaccuracies. Not surprisingly, Neisser embraced Bartlett's observations and ideas about the nature of memory."
Schacter, 1995, p.10
These ideas will not seem strange to those who have studied science education, a field which has been strongly influenced by a 'constructivist' perspective on learning. Drawing on learning science research, the constructivist perspective focuses on how each learner has to build up their own knowledge incrementally: it is not possible for a teacher to take some complex technical knowledge and simply transfer it (or copy it) to a learner's mind wholesale.
Excavating the analogy: what did Hebb actually say?
Hebb is remembered for his work on understanding the brain in terms of neural structures – neurons connected into assemblies through synapses. His book 'The Organization of Behavior' has been described as "one of the most influential books in Psychology and Neuroscience" (Brown, 2020: 1).
The analogy referred to by Schacter was used by Hebb in describing perception. He discussed studies using a tachistoscope, an instrument for displaying images for very brief periods. This could be used to show an image to a person with an exposure insufficient for them to take in all the details,
"…the pattern is perceived, first, as a familiar one, and then with something missing or something added. The something, also, is familiar; so the total perception is a mélange of the habitual.
The subject's reports [make it] clear that the subject is not only responding to the diagram as a whole; he perceives its parts as separate entities, even though presentation is so brief. Errors are prominent, and such as to show that all the subject really perceives–and then only with rough accuracy–is the slope of a few lines and their direction and distance from one another"
Hebb, 1949: pp.46-47
That is, the cognitive system uses the 'clues' available from the incomplete visual data to build (in effect) a hypothesis of what was seen, based on correspondences between the data actually available and familiar images that match that limited data. What the person becomes consciously aware of 'seeing' is not actually a direct report from the visual field of the presented image, but a constructed image that is a kind of conjecture of what might have been seen – 'filling-in' missing data with what seems most likely based on past visual experiences.
Cognitive scientist Annette Karmiloff-Smith developed the concept of 'representational redescription' as a way of describing how initially tacit knowledge could eventually become explicit. She suggested that "intra-domain and inter-domain representational relations are the hallmark of a flexible and creative cognitive system" (Karmiloff-Smith,1996: 192). The gist was that the brain is able to re-represent its own internal representations in new forms with different affordances.
An loose analogy might be someone who takes a screenshot when displaying an image from the JPEG photo collection folder on the computer, opens the screenshot as a pdf file, and then adds some textual annotations before exporting the file to a new pdf. The representation of the original image is unchanged in the system, but a new representation has been made of it in a different form, which has then been modified and 'stored' (represented) in a different folder.
Hebb was describing how a representation of visual data at one level in the cognitive system has been represented elsewhere in the system (representational redescription?) at a level where it can be mentipulated by 'filling-in'.
Hebb then goes on to use the analogy:
"A drawing or a report of what is seen tachistoscopically is not unlike a paleontologist's reconstruction of early man from a tooth and a rib. There is a clear effect of earlier experience, filling in gaps in the actual perception, so that the end result is either something familiar or a combination of familiar things–a reconstruction on the basis of experience."
Hebb, 1949: p.47
Teaching analogies
Hebb was writing a book that can be considered as a textbook, so this can be seen as a teaching analogy, although such analogies are also used in communicating science in other contexts.
Teaching is about making the unfamiliar familiar, and one way we do that is by saying that 'this unfamiliar thing you need to learn about is a bit like this other thing that you already know about'. Of course, when teaching in this way we need to say in what way there is an analogy, and it may also be important to say in what ways the two things are not alike if we do not want people to map across irrelevant elements (i.e., to develop 'associative' learning impediments).
Hebb is saying that visual perception is often not simply the detection of a coherent and integral image, but is rather a construction produced by building upon the available data to construct a coherent and integral image. In extremis, a good deal may be made of very little scraps of input – akin to a scientist reconstructing a model of a full humanoid body based on a couple of bits of bone or tooth.
Hebb's analogy
There are examples where palaeontologists or anthropologists have indeed suggested such complete forms based on a few fossil fragments as data. This is only possible because of their past experiences of meeting many complete forms, and the parts of which they are made. (And of course, sometimes other scientists completely disagree about their reconstructions!)
An exscientific analogy?
Often in teaching science we use teaching analogies that compare an unfamiliar scientific concept to some familiar everyday phenomenon – perhaps a reaction profile is a bit like a roller-coaster track. Perhaps we could call these adscientific analogies as the meaning is transferred to the scientific concept from the everyday.
Sometimes, however, familiar scientific phenomena or ideas are used as the source – as here. Perhaps these could be called exscientific analogies as the meaning is taken from the science concept and applied elsewhere.
Developing the palaeontology analogy
So, Hebb had originally used the palaeontology analogy in the context of discussing perception. When I looked into how Neisser had used the comparison in his "important monograph on cognitive psychology" I found he had developed the analogy, returning to it at several points in his book.
Do we analyse what we attend to?
Neisser's first reference was also in relation to perception, rather than memory. Neisser argued that before we can attend to part of a scene there must already have been the operation of "preattentive mechanisms, which form segregated objects" from which we can select what to attend to. These processes might be referred to as analyses:
"…the detailed properties and features that we ordinarily see in an attended figure…arise…only because part of the input was selected for attention and certain operations then performed on it. Neither the object of analysis nor the nature of the analysis is inevitable, and both may vary in different observers and at different times."
Neisser, 1967, p.94
But Neisser was not sure this really was 'analysis', which he understood as drawing on another (what I labelled above) exscientific analogy:
"The very word 'analysis' may not be apt. It suggests an analogy with chemistry: a chemist 'analyses' unknown substances to find out what they 'really' are."
Neisser, 1967, p.94
Rather than refer to analysis, we could draw on Hebb's palaeontological analogy:
"More appropriate…is Hebb's (1949, p.47) comparison of the perceiver with a paleontologist, who carefully extracts a few fragments of what might be bones from a mass of irrelevant rubble and 'reconstructs' the dinosaur that will eventually stand in the Museum of Natural History. In this sense it is important to think of focal attention as a constructive, synthetic activity rather than as purely analytic. One does not simply examine the input and make a decision; one builds an appropriate visual object."
Neisser draws upon the analogy repeatedly in developing his account of perception:
"Such emotion-flooded experiences [as 'physiognomic' perception: 'Everyone has perceived such traits as suppressed anger in a face, gaiety in a movement, or peaceful harmony in a picture'] can be thought of as the result of particular kinds of construction. The same fragments of bone that lead one paleontologist to make an accurate model of an unspectacular creature might lead another, perhaps more anxious or more dramatic, to 'reconstruct' a nightmarish monster." (pp.96-97)
"To 'direct attention' to a figure is to attempt a more extensive synthesis of it. Of course, synthesis presupposes some prior analysis, as the paleontologist must have some fragments of bone before he can build his dinosaur…" (p.103)
"Recognition, whether of spelling patterns or words as wholes, must be mediated by relevant features, as meaningless in themselves as the bone chips of the paleontologist." (p.114)
"The process of figural synthesis does not depend only on the features extracted from the input, just as the dinosaur constructed by a paleontologist is not based only on the bone chips he has found. Equally important is the kind of perceptual object the perceiver is prepared to construct. The importance of set and context on the perception of words has been demonstrated in a great many experiments." (pp.115-116)
Neisser, 1967
And as with perception, so memory…
When Neisser discusses memory he uses a kind of double analogy – suggesting that memory is a bit like perception, which (as already established) is a bit like the work of the palaeontologist:
"Perception is constructive, but the input information often plays the largest single role in determining the constructive process. A very similar role, it seems to me, is played by the aggregate of information stored in long-term memory.
This is not to say that the stimuli themselves are copied and stored; far from it. The analogy being offered asserts only that the role which stored information plays in recall is like the role which stimulus information plays in perception….The model of the paleontologist, which was applied to perception and focal attention in Chapter 4, applies also to memory: out of a few stored bone chips, we remember a dinosaur….one does not recall objects or responses simply because traces of them exist in the mind, but after an elaborate process of reconstruction, (which usually makes use of relevant stored information).
What is the information – the bone chips – on which reconstruction is based? The only plausible possibility is that it consists of traces of prior processes of construction. There are no stored copies of finished mental events, like images or sentences, but only traces of earlier constructive activity."
Neisser, 1967, p.285
Fleshing-out the metaphor
Neisser then pushes the analogy one step further, by pointing out that the 'fleshed-out' model of a dinosaur in the museum may be constructed in part based on the fossil fragments of bones, but those fragments themselves do not form part of the construction (the model). The bones are used as referents in building the skeletal framework (literally, the skeleton) around which the model will be built, but the model is made from other materials (wood, steel, fibreglass, whatever) and the fossil fragments themselves will be displayed separately or perhaps filed away in a drawer in the museum archives. (As in the representational redescription model – the original representation is redescribed at another level of the system.)
"The present proposal is, therefore, that we store traces of earlier cognitive acts, not of the products of those acts. The traces are not simply 'revised' or 'reactivated' in recall; instead, the stored fragments are used as information to support a new construction. It is as if the bone fragments used by the paleontologist did not appear in the model he builds at all – as indeed they need not, if it to represent a fully fleshed-out skin-covered dinosaur. The bones can be thought of, somewhat loosely, as remnants of the structure which created and supported the original dinosaur, and thus as sources of information about how to reconstruct it."
Neisser, 1967, pp.285-286
Neisser's development of Hebb's analogy
The head palaeontologist?
A final reference to the analogy is used when Neisser addresses the question of the cognitive executive: the notion that somewhere in the cognitive system there is something akin to an overseer who direct operations:
"Who does the turning, the trying, and the erring" Is there a little man in the head, a homonculus, who acts the part of the paleontologist vis-à-vis the dinosaur? p.293
Neisser, 1967, p.293
The homonculus can be pictured as a small person sitting in the brain's control room, for example, viewing the images being projected from the visual input.
It is usually considered this is a flawed model (potentially lading to an infinite regress), a failure to take a systemic view of the cognitive system. It is the system which functions and leads to our conscious experience of perceiving, attending, making decisions, planning, remembering, and so forth. Whilst there are specialist components (modules) including for the coordination of the system, there is not a discrete controller overlaying the system as a whole who is doing the seeing, hearing, thinking, etcetera based on outputs from processing by the system.
Here the homonculus would like an authority that the palaeontologist turned to in order to decide how to build her model: raising the question of how does that expert know, and who would they, in turn, ask?
Why change Hebb's orignal analogy?
Altohugh Neisser refers to the analogy as being that used by Hebb, he modifies it. A tooth and rib become fragments of bone, and the early man becomes a dinosaur. Whether the shift from the reconstruction of an early hominid to the reconstruction of a terrible lizard was a deliberate one (for greater effect? because Neisser thought it would be more familiar to his readers?) or not I do not know. The phrasing suggests that Neisser thought he was applying Hebb's original comparison – so I suspect this is how he recalled the analogy.
Perhaps Neisser had regularly used the analogy in his teaching, in which case it may have become so familiar to him that he did not feel the need to check the original version. That is, perhaps he was correctly remembering how he had previously misremembered the original analogy. That is not fanciful, as memory researchers suggest this is something that is very common. Each time we access a memory the wider representational context becomes modified by engagement with it.
That is, if what is represented (in 'long-term memory'*) is indeed "traces of prior processes of construction…traces of earlier constructive activity" then each time a 'memory' is experienced, by being constructed based on what is represented ('in memory'*), new traces of that process of constructing the memory are left in the system.
It is possible over the years to be very convinced about the accuracy of a distorted memory that has been regularly reinforced. (The extent to which this may in part be the origin of many wars, feuds, and divorces might be a useful focus for research?)
So perhaps Neisser had represented in his long-term memory the analogy of a palaeontologist with a few fossil fragments, and when he sought to access the analogy, perhaps in a classroom presentation, the other elements were filled-in: the 'tooth and rib' became 'a few fragments of what might be bones' and the 'early man' become 'a dinosaur' – details that made sense of the analogy in terms familiar to Neisser.
The account of cognition that Hebb, Neisser and Schater were presenting would suggest that if this had been the case then for Neisser there would be no apparent distinction between the parts of Hebb's analogy that Neisser was remembering accurately, and the parts his preconscious mind had filled-in to construct a coherent analogy. I like the reflexive nature of this account – of someone reconstructing an analogy about how cognition reconstructs coherent wholes from partial, fragmented data – from a partial, fragmented memory representation.
Sources cited:
Bartlett, F. C. (1932/1995). Remembering: A study in experimental and social psychology Cambridge: Cambridge University Press.
Brown, R. E. (2020). Donald O. Hebb and the Organization of Behavior: 17 years in the writing. Molecular Brain, 13(1), 55. doi:10.1186/s13041-020-00567-8
Hebb, D. O. (1949). The Organisation of Behaviour. A neuropsychological theory. New York: John Wiley & Sons, Inc.
Karmiloff-Smith, A. (1996). Beyond Modularity: A developmental perspective on cognitive science. Cambridge, Massachusetts: MIT Press.
Neisser, U. (1967). Cognitive Psychology. New York: Appleton-Century-Crofts.
Schacter, D. L. (1995). Memory distortion: history and current status. In D. L. Schacter (Ed.), Memory Distortion. How minds, brains, and societies reconstruct the past (pp. 1-43). Cambridge, Massachusetts: Harvard University Press.
* terms like 'in memory' and 'in long-term memory' may bring to mind the folk-notion of memory as somewhere in the brain where things are stored away, whereas it is probably better to think of the brain as a somewhat plastic processing system which is constantly being modified by its own functioning. The memory we experience is simply the outcome of active processing** in part of the system that has previously been modified by earlier mental activity (** active processing which is in turn itself further modifying the system).
