Seminar at UCLES
The constructivist view of learning: how can it inform assessment?
Research Symposium:
The constructivist view of learning: how can it inform assessment?
Dr. Keith Taber
Faculty of Education, University of Cambridge
an invited presentation
to the
University of Cambridge Local Examinations Syndicate (UCLES)
Research and Evaluation Division (RED)
Monday 27th May 2002, 10.30-12.30
Furness Lodge, Regent Street, Cambridge
Keith S. Taber 2002
Dr. Keith Taber
University of Cambridge Faculty of Education
Homerton Site
Hills Road
Cambridge CB2 2PH
The constructivist view of learning:
how can it inform assessment?
Dr. Keith S. Taber
Faculty of Education
Abstract:
The constructivist perspective has been a dominant influence on the direction of much research into learning science for the past two decades. The notion that students come to science classes already possessing a wealth of ‘intuitive’ or ‘alternative’ science has inspired a great deal of work designed to elicit children’s ideas about science topics – before, during and after formal teaching.
The research programme has matured, and should now be in a position to inform educational practice – although sadly any general consensus on many points seems to be lacking. Although ideas from the field are now taken for granted, and teachers are expected to demonstrate this in their practice, curriculum design at a national level has not been significantly influenced by the key principles.
One of the areas of general agreement is that learners’ ideas need to be elicited, and taken into account, when planning teaching. This seminar will look at how this process might be (and sometimes is) executed in classroom contexts. In particular a Royal Society of Chemistry project (‘Challenging Misconceptions in the Classroom’), designed to support teachers in carrying out diagnostic assessment, will be discussed.
The seminar will also consider how this area of research relates to more formal aspects of testing, and raises some fundamental questions about what we should be assessing in science (and other curriculum areas) in view of what we now believe about the way learning takes place. In science in particular, there is a widespread concern that learners often fail to appreciate the nature of science as an activity, and - in this respect - current approaches to assessing science may well be part of the problem.
Introduction
I was very pleased to be invited here today to talk to the Research and Evaluation Division about my work. I was also somewhat apprehensive on two counts: firstly that what I have to say about learning in science may be too parochial to be of value to colleagues here, and secondly (and somewhat in contrast) that anything I say about assessment may be seen as rather naive and ill-informed!
However, the theoretical background I use in my own work is somewhat eclectic, drawing on ideas from a range of fields, and as you have been kind enough to invite me, I will trust that (in the same spirit) some of what I say may usefully connect with your work here in UCLES.
My background is in science education, and I am aware that not everyone here today is likely to be a scientist. The area of research I will be talking about is (not exclusively, but largely) from within science education, as are my examples; but I believe that the relevance of the ideas is far wider, and so I hope the significant science bias in the presentation will be acceptable.
I will begin by considering a perspective on learning in science which has been very influential in recent years, both in some aspects of teaching practice, and in particular in terms of research. This approach, often called constructivism, is not well-defined (despite much literature on the topic) and so the version I will present has my own flavour and should not be seen as an authoritative definition of the field.
One of the main practical outcomes of this area of work is the recognition of the importance of eliciting learners’ ideas, and this clearly connects with assessment, and - in particular - diagnostic assessment. I will discuss this topic, and I will refer in particular to a Royal Society of Chemistry funded project to support teachers in this aspect of their work.
However, I also feel that there are two other aspects of this area of research which are of particular significance for assessment. The first of these relates to notions of ‘scaffolding’ learning, and the concept known as the ‘zone of proximal development’. I think this topic is especially relevant to the ways that formal (summative) assessment questions have changed over recent decades.
The other theme relates to much of the criticism that the examinations system currently faces from teachers (as anyone who subscribes to teachers’ discussions lists will be well aware), and that is the way that science teaching in this country is often considered to be ‘assessment-led’, or at least ‘highly assessment-constrained’. Research suggests that the image of science that learners develop during their schooling is very distorted, and part of the blame is sometimes considered to relate to the way we assess students.
The constructivist perspective on learning.
At this point in time the constructivist view of learning seems little more than common sense, so perhaps I should begin by briefly considering the alternative. In this view (which now seems ridiculous, but seems to have been the tacit theory on which education operated for a long time, and which is still evidenced in much of the behaviour of many teachers) the learner starts as a tabula rasa, a blank slate on which impressions may be made. The role of the teacher was to transfer accepted knowledge to the learner through teaching (e.g. dictating or presenting on the board a set of accurate and comprehensive notes). Providing the learner was present, attentive, and able to receive the communication (e.g. within hearing range, able to see the board, given time to write everything down neatly), then learning should be possible - presumably by the learner reading through their notes a sufficient number of times before the examination.
This seems such a naive approach that as I write these words I even begin to doubt it was ever this way: but then on reflection I suspect there is still much teaching which in practice is still built upon such a model. Certainly the National Curriculum (NC) implies that there is a great amount of knowledge to be acquired by students: surely too much content for teachers to encourage students to take a reflective approach to developing understanding in science?
What is missing in such a description of learning is any notion of the active role of the learner. Perhaps this reflects a behaviourist influence, where anything inside the head that could not be observed and measured should be ignored.
Yet if this model had any validity teaching would be easy, and motivated students should all score close to full marks on formal assessments. In practice we know that even the keenest learners do not always easily understand difficult concepts, and that much of what is ‘taught’ is not ‘remembered’ at the point of assessment.
I put the word ‘taught’ in inverted commas as there is an adage in education that teaching has only taken place when learning occurs! On that standard much of what teachers do needs a different name: presenting perhaps? So, much of what is presented by teachers is not ‘remembered’ at the point of assessment.
I put the word ‘remembered’ in inverted commas for a different reason, which is that this must here be seen as a generic term from a number of processes. At one level there is the simple distinction between ‘recall’ and ‘recognise’ - i.e. it is easily to acknowledge that something is familiar than it is to access it from memory when it is not being perceived.
This is just part of a much bigger question of what is involved in remembering. The distinction between recognition and recall illustrates the significance of the contextual cues provided when eliciting information (an important theme that will be returned to later in this paper), but also touches upon the question of the extent to which memory is a process of knowledge reconstruction rather than straight retrieval of stored information.
In other words there is no doubt that we store information in memory, but there is much uncertainty about how we achieve this. We do not know at what ‘grain size’ the information is stored, or how associated knowledge is connected within cognitive structure. It could be that some complex information is stored as a unified complex, or that it is stored in modular form, and needs to be reconstructed when memory is accessed. As the ‘associations’ between items [sic] in memory may be of different and variable strengths such a distinction may suggest a dichotomy between the two possibilities, when the actual situation may be better seen as a continuum.
As this may be an important question for those working in assessment it is perhaps only fair that I acknowledge at this point that I do not have a definitive answer to that question, but my own view based on my reading and my own experience as a teacher and researcher is that the real question should be about the extent to which any particular act of memory is a process of knowledge reconstruction rather than retrieval of stored information.
Where data is habitually presented together and perceived to have a strong and constant relationship it seems likely that the memory trace reflects this (so that young people today are more likely to associate Nelson with Mandela than with Horatio). But we are also able to solve problems by forming novel associations between different stored items, so that a student can use memory to work out the shape of the PCl3 molecule even if that is not one of the standard examples studied, by accessing separate stored information about the model used to assign shapes to molecules, and about the specific molecule. (And if the student has never thought about the structure of that particular molecule then that may first have to be compiled from other knowledge about the periodic table etc.)
I should point out that although these examples suggest that memory is being used to construct a new association, there is much evidence that even when we ‘remember’ familiar events we are actually reconstructing the memory from stored fragments, and filling-in missing details to give the memory overall coherence. (It is no wonder that witness testimony in court cases is so often found to unreliable: we often seem to have clear memories of events, quite unaware of the extent to which missing details have been compensated for with best guesses.)
This consideration of remembering provides a useful link with the problem of how we form memories of course material in the first place. The constructivist view sees the learner as having to construct knowledge (thus the term constructivism!) rather than absorb knowledge wholesale. This does not mean that a student will not come to an acceptable understanding of what is meant by capacitance, oxidation or photosynthesis (or watershed, verb, reformation, diminished fifth, or unemploydestagflation, etc.) - however, the student will not acquire an acceptable meaning of some concepts wholesale, ab initio, by a discrete act of learning.
Learning is restricted in at least three ways:
a) only a limited amount of material can be kept in mind at once - information that ‘seems’ complex may exceed this ‘processing capacity’;
b) for new information to be ‘meaningful’ it has to be understood to be relevant to prior learning;
c) permanent memories are only laid down hours after the initial presentation, and substantial restructuring of knowledge may take place over much longertime-scales (months and years).
If it seems (sic) odd for me to refer to how information ‘seems complex’ then this is because what is significant is not how complex information may seem to the expert (e.g. the teacher, much more familiar with the ideas, and already aware how they fit into the wider scheme), but the complexity of the material as it appears at ‘the resolution’ of the particular learner.
Alternative conceptions.
Given such a perspective it seems less surprising that teaching is such a skilled craft, and that failures of learning/teaching are so common (and thus the need for exam boards to set pass marks and grade boundaries!)
The other consequence of this view that has been the centre of much interest within science education is the importance of learners’ ideas about a subject. The constructivist view on learning emphasises how meaningful learning (cf. rote learning) occurs when the learner associates the new information with something seen as relevant within their existing knowledge. The learner’s existing cognitive structure acts as the substrate or substratum for new learning. Meaningful learning occurs when the learner is able to anchor new information to that bedrock of existing knowledge. As the body of existing knowledge may include various alternative conceptions, and as new information may be judged to be relevant to prior learning in unintended ways, such learning need not be appropriate just because it is meaningful.
For one thing, people are learners per se, not just when placed in classrooms. We all learn all the time. Young children actively explore and interpret their worlds and develop knowledge from a very young age.
For example, children commonly develop a view of force and motion which is heavily based on experience, but unfortunately not well matched to scientific knowledge. Whereas experience of the world says a force is needed to maintain motion, school physics says otherwise, and the physics teacher has to somehow overcome the students’ tendency to rely on their long-standing, and well evidenced, view of the world.
‘Common sense’ and interpreting the world around them, ‘teaches’ children that plants grow in the soil, and are sometimes ‘fed’ by having plant food or fertiliser added to the soil. The soil also needs to be watered if the plant is not to die. Clearly then the growth of plants is due to them drawing materials from the soil. Unfortunately the school science version is a little different, with a key role given to the absorption of carbon from the atmosphere - something for which there is no support from everyday experience.
As a child’s life is not a carefully planned set of experiences designed to bring them to curriculum knowledge it is hardly surprising that they exhibit a wide range of alternative conceptions such as ‘constant velocity implies constant force’ and ‘the matter in a tree comes from the soil’.
Things do not necessarily get easier when the child reaches school age, as they are still subject to many other sources of information (including family, peers, media etc.) which need not be fully accurate, and they are now making sense of new information by interpreting it in terms of what they already think they know!
There has now been a vast research exercise exploring students’ ideas in various science topics at different educational levels, and invariably learners have been found to understand scientific topics in ways that are alternative to the versions taught in the curriculum. The teacher’s role is certainly not to impress upon the blank slate of the student’s mind to replace ignorance, but rather often to develop existing alternative knowledge about a topic.
Requirements of effective teaching?
Considering what has been outlined it would seem that effective teaching requires the teacher to:
a) analyse the logical structure of a topic and to identify all the prerequisite knowledge that is required;
b) check that the learners have already learnt conventional versions of that prerequisite knowledge;
c) introduce the new knowledge (i) in ways that clearly build upon the prerequisite knowledge, and (ii) at a rate that does not overload students.
This is a tall order when working with a single learner, and becomes close to an impossible task with a class where each individual student has distinct background knowledge (each including some idiosyncratic alternative conceptions) and where learners are able to process information at different rates and in different sized aliquots!
The importance of diagnostic assessment.
However, this prescription does emphasise that it is important for teachers to have a good knowledge of what prior learning can be assumed when teaching any topic. (And you will recall my own comments that presaged this paper: I have had to make assumptions about this audience’s prior learning. To the extent that I have guessed wrong you will either be confused or bored, or you may even be experiencing a mixture of confusion and boredom!)
During initial training science teachers are now taught the importance of pupils’ conceptions, and are encouraged to actively check out prior learning at the start of a topic. It is considered that time spent on this activity should be well-spent, hopefully avoiding some of the worst inefficiencies of repeating familiar material (without developing it further) or talking over the heads of the class.
In research idiographic methods of exploring learners’ ideas have often been found to be more effective than survey-type approaches. The semi-structured interview is the technique of choice for the alternative conceptions researcher, but such approaches are too time consuming to be used formally by classroom teachers. (Of course, much informal formative assessment in the classroom is through teacher questioning which is similar in nature to much research interviewing - with one very important distinction which will be considered later.)