Saturday, 2 January 2010

Knowledge first, critique later

Knowledge first, critique later: Why it is a mistake for science education to encourage junior students to discuss, challenge and debate scientific knowledge

Bruce G. Charlton

Medical Hypotheses. 2010; 74: 211-213.


In UK educational circles it has long been regarded as a platitude that a good scientific education at school and undergraduate level should aim to teach critical thinking and encourage students to challenge mainstream science, debate scientific issues and express their personal opinions. However, I believe that this strategy is usually mistaken, and that such educational strategies probably do more harm than good. For most students, at most levels, for most of the time; science education should be focused on the inculcation of established knowledge. This is for the simple reason that critique is educationally-counterproductive and scientifically-worthless unless or until underpinned by adequate knowledge and competence. Instead, for the early years of science teaching, the basic assumption ought to be that the student is there to learn science; not to confront science. The basic attitude being taught should be one of humility before the science being studied.


Should junior science students be encouraged to challenge and debate?

In UK educational circles it has long been regarded as a platitude that a good education at both school and undergraduate level should teach critical thinking, encourage students to challenge what they are taught and to debate scientific issues. The perceived need to encourage critique among students is especially asserted for science, since it is (correctly) recognized that scientific progress depends upon challenging and replacing pre-existing ideas.

So strong is this supposition of the virtue of classroom discussion of scientific knowledge, that people who state that science education ought to focus on training in critical thinking are not required to support or argue further for this belief – it is simply assumed to be correct. The model is that students from early school years up through undergraduate college should study science by (in a sense) simulating the scientific discovery process: by asking questions, generating hypotheses, doing ‘research’, framing criticisms, performing analysis and drawing conclusions (although, typically – and necessarily, it is pre-determined that only a narrow range of conclusions will count as acceptable).

I believe that the common conviction of the importance of critique or debate in basic scientific education is a serious mistake, with only a few unusual and particular exceptions to this stricture. On the contrary, to be helpful student dispute or classroom discussions of the validity of scientific questions must always be underpinned by high-level competence among the participants (teachers and students both), including sufficient knowledge and requisite skill in reasoning. Otherwise classroom discourse among student is of no greater educational value than if they were engaged in playground, pub or party gossip concerning current affairs – it is a mere venting of superficial views or ‘shooting the breeze’.

Indeed, insofar as barely-informed (or wholly un-informed) students discussion is taken seriously (by teachers or other students) it is counter-productive. Given the extreme difficulty of making a genuine contribution to science (and the fact that, sadly, even most professional scientists fail to do this); it is surely implausible to imagine that it is usually a useful exercise for uneducated non-scientists to engage in debate about the validity of scientific theories or data.

Requesting most students to spent a few hours ‘researching’ a topic may slightly-dent but will be far from demolishing their basic ignorance except when the student is exceptionally motivated, intelligent and well-prepared. Educationally-meaningful classroom discussion will requires a quorum of such bright and well-prepared students, and also careful management of the conversation. And, most students own personal evaluations and theories on scientific topic will very seldom meet even minimal intellectual standards: their educational value is mainly in (of course gently and tactfully) providing ‘bad examples’ for the teacher to critique and modify.

Pandering to self-esteem

My interpretation of the popularity of un-informed discussion and debate about scientific issues is that it is mainly a matter of pandering to the natural desire which some people have to pontificate and show-off, and to be taken seriously when doing so (a vice which is probably almost as common among students as it is among their teachers!). Semi-structured debate on topics about which students are essentially ignorant is at best a more-or-less amusing waste of time but more often is probably somewhat harmful, insofar as it creates a delusion of competence.

Perhaps class discussions are done to improve student ‘self-esteem’? (Self-esteem being a current mantra among educationalists.) Unfortunately for this idea, considerable evidence suggests that self-esteem is inversely correlated with educational attainment. High self-esteem apparently breeds complacency, while it seems that low self-esteem may be a motivation for students to learn. And in terms of scientific criteria an average student realistically ought to have low self-esteem; since most students most of the time are likely to be scientifically ignorant, unskilled and only minimally-interested in the subject of study.

Since the objective of science education is to teach a science, then it follows that the proper scientific role of classroom discussion in low-level education is not to air student’s opinions on a subject they are far from having learned; nor to allow them to pretend to engage in ‘research’, evaluate evidence, solve scientific problems or suggest new theories – but instead for teachers to ask and to answer questions.

And when the teacher is answering questions, the underlying assumption behind these questions must usually be that the science being taught is broadly correct and the student’s job is to understand and learn it. Where the student disagrees with the science being taught, the supposition must be on both sides that this question is needed because the student has not properly understood or lacks contextual information. So, when the student feels they disagree, the student should not be questioning the science, but implicitly asking for clarification.

A student’s need for clarification may be due to inattentiveness, ignorance, or inability on their part; or to something having gone wrong with the teaching; or simply because difficult concepts being encountered for the first time often need to be explained several times in several different ways. But as a rule, there is no warrant to challenge the validity of the science at this point.

Given that adolescence is often the stage at which personality is at its most prickly and arrogant (due to this being around the average age at which the traits of conscientiousness and agreeableness are at their lowest and levels of extraversion and neuroticism at their highest) it is particularly important that the educational system be consistent in instilling an appropriate degree of intellectual humility in line with students typically undeveloped levels of competence. Encouraging pre-teens or teenagers to believe that they can settle the debates of science (or other scholarly subjects) in class discussion on the basis of an evening of ‘Googling’ is simply telling people what they want to hear.

The presumption of ignorance and incompetence on the part of the student is, of course, one that naturally dwindles as a student advances through the educational system and specializes in a particular science. Eventually, if a good student studies a subject for long enough (probably during the doctoral stage) the presumption may switch around. At this point a bight student’s concerns in the area of their expertise may plausibly be taken to be to evidence of a potential problem in the science, rather than a problem in the ability or knowledge of the student.

Critical discussion by students then and now

If the above argument is accepted, then it is interesting to speculate how it was that the idea ever got off the ground that students had sufficient expertise to replicate (in a few hours) the discovery process, or to critique science. There is a large element of politically-correct nonsense, wishful-thinking and professional self-serving dishonesty about all this – of course – but perhaps there is also a germ of plausible observation as well. I personally suspect that the mistaken expectation of student expertise may arise from the elite selectivity and early specialized training of past generations of scientists.

In the UK during the mid-twentieth century, the university system used to take only about 5% of the age cohort – and by about 1980 it was still only around 15%. Furthermore, professional scientists had mostly been educated at selective ‘grammar schools’ in which academic specialization began at age 14. Universities only accepted students for science degrees if they had good qualifications at A-level (three scientific subjects studied for 2 years 16–18), and the UK undergraduate science degrees were further narrowly specialized, and built upon this advanced and specific level of preparation of selective schools.

Children at the most elite selective schools were then reaching a level of specialist knowledge that would seldom be attained at the bachelor’s degree level nowadays. Some such students would be capable of meaningful and useful critique of existing science even before they attended university, or more often within a couple of years at undergraduate level. Keen undergraduates at the best universities were rapidly able to advance their scientific knowledge to the cutting-edge; and during their undergraduate degree, or immediately after graduation, they would be capable of embarking on independent research.

But nowadays in the UK nearly half of 18 years old attend higher education institutions to study for some kind of undergraduate degree – nearly a 10-fold reduction in the selectivity of average undergraduates. Furthermore, the link between the subject matter of school study and university study has been broken, so that university teachers can no longer rely upon the students having studied specific relevant and advanced science at school.

Modern UK students with a bachelor’s degree may only have studied science for 3 years, and often in low-volume, low-intensity curricula where it is very unusual to fail examinations. Modern students therefore seldom get far enough in their subject to be able meaningfully to discuss science at the cutting-edge, until they have finished their undergraduate degree and are reasonably-advanced in their post-graduate/graduate school training.

Aiming-high and missing

A more practical pedagogical problem – but one which I would regard as highly significant – is that it is very hard for students to learn difficult concepts unless these concepts are presented as unambiguously as possible.

Ambiguity interferes with learning, since each additional possibility multiplies uncertainty in a geometric fashion. I am not sure whether this is numerically exact, but it seems as if adding the first uncertainty to an explanation doubles the cognitive load – because there are now two parallel and diverging possibilities; both of which must now be known, understood and compared. Adding a second uncertainty to the first therefore quadruples the cognitive load, a third uncertainty will render comprehension and memorizing 16-fold more difficult – and so on.

This analysis implies that the primary mode of most science teaching must be dogmatic; that is to say, a science teacher must initially make a choice about the single most correct interpretation of evidence and the single most correct conclusion – and must restrict the initial presentation to this clear and simple exposition.

Only after the teacher is confident that most students have understood this clear and simple account (and preferably after leaving this unified exposition to be assimilated over-night) should the teacher add layers of uncertainly, debate, dissention and complication to the simple account. Premature challenging of mainstream science, debates over competing hypotheses, and uncertainties engendered by free-form discussions are likely to interfere with learning.

Therefore, for many students studying science, it is better to leave them with a clear grasp of the single best version of a concept, than permanently to confuse them with further accounts; or potentially to drive-out or corrupt a clear and approximately-accurate memorization by interference from related – similar but not quite equivalent – explanations, qualifications and nuances.

Obviously, this does not mean the science classroom should be a wholly one-way street of discourse streaming from the teacher into the taught – of relentless pontification from one side and silent absorption on the other side. On the contrary, student feedback (via perceived visual signals and some spoken enquiries or comments) is necessary for the teacher to monitor the learning process. (This is one reason why real time, real life lectures retain their value; and why to be successful lectures need small-enough and well-designed lecture rooms such that the lecturer and his audience remain in sensory contact.)

Science teaching could and should be made more interesting for students than it usually is – but it should be made more interesting while still being science; and not at the cost of stopping studying science and instead engaging in mere science-themed chit-chat. In reality, the flow of scientific knowledge is likely to be unidirectional.

If teachers aim too-high for students whose motivation, intelligence and preparation are insufficient; or if teachers try to make students run before they can even crawl – especially for students who lack the background and ability ever to do anything more than walk; or if teachers overwrite their clearest and simplest message by smothering it in confused discussions and pseudo-scientific debates – then teachers risk failing to enable the attainment of even basic scientific knowledge and competence in their students.

Instead, for the early years of science teaching, the basic assumption ought to be that the student is there to learn science; not to confront science. The basic attitude being taught should be one of humility before the science being studied.