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Categorisation and concept development

Linda Gilmore

The interaction between individual and environment is simplified by dealing with categories of things rather than with unique events or objects. As Glass et al (1979, p.327) point out, categorisation is a 'powerful tool for organising memory and thought'.

A study of categorising behaviour may provide information about concept development since concepts exist when objects or events are grouped together on the basis of some common feature (Bourne, 1971, p 415).

Younger children appear to be more preoccupied with perceptual aspects, recognising the physical rather than abstract properties of objects. They are likely to categorise according to a single physical characteristic (such as colour, shape or size) whereas older children and adults more often focus on a number of more complex and more abstract features (for example, functional and social, as well as perceptual) in line with the more complex bodies of concepts they possess (Stones, 1979; Bruner et al, 1966; Bourne, 1971).

This paper reports on a task involving the categorisation of objects by children, adolescents and young adults to provide information about concept development at different ages.


Three subjects from each of three age groups (children 7-10 years; adolescents 13-15 years; and young adults) were individually asked to sort 30 objects into 'groups of things that go together'. Table 1 lists the randomly arranged objects which were presented.

Table 1: Objects for Categorisation

  1. teabag in packet
  2. medicine glass
  3. key
  4. hook
  5. button
  6. screw
  7. cork
  8. blue comb
  9. battery
  10. small book
  11. postcard
  12. toy man
  13. toy block
  14. packet tablets
  15. white string
  1. shell
  2. pencil
  3. blue plastic peg
  4. rubber
  5. round coaster
  6. metal spoon
  7. plastic drink stirrer
  8. blue bottle top
  9. white dice
  10. metal hair clip
  11. rock
  12. toy car
  13. small bottle
  14. photo in frame
  15. glass ornament

Each subject had to decide on the categories to be used and select objects to fit those categories. The subject was also free to choose the number of groups formed and thus the size of those groups.


A comparison of the type of categories used by each age group is shown in Table 2.

Table 2: Concepts Used in Categorising

Age GroupShapeSizeMaterialColourFunction

13-15XXX XX


Table 3 presents a graph showing the average size of groupings at each age level. 'Size' is taken as meaning the number of objects in a group.

Table 3: Average Group Size

Table 3

As expected, grouping strategies varied with age. The young children approached the task with the most confidence and quickly grouped objects according to their obvious physical similarities of shape. They grouped objects, not because they were similar kinds of objects, but because they shared common shapes. This focus is not surprising since concepts are based on prior experience and shape concepts are acquired early - being readily identified, precisely defined and easily distinguished from each other.

The adolescent group regarded this task as a challenge. They were particularly keen to select criteria that would result in neat groupings with no left-over objects. Perhaps the most interesting feature of the groupings was that each adolescent employed a variety of concepts for categorising, rather than the single criterion used by each young child and adult.

Adolescent subjects combined the criteria of shape, colour, size, material and function in forming their groups. Such a range may reflect the fact that this age group is more used to using a variety of concepts in problem solving. Perhaps they think in more diverse and adept ways than younger children and adults who use a more 'one-track' approach in their thinking. Or it may mean that adolescents have not yet reached the adult stage of mostly disregarding physical properties of objects when considering their main criterial attributes.

The adult group experienced most difficulty with the task. Two subjects employed the criterion of function, while the third used materials. One adult formed one large group of nearly half the objects, on the basis that they were simply all 'odds and ends' expressing an inability to form any other connections between items. Each adult was, however, left with one or more single items that could not be grouped which may, as Wallach and Kogan (1965) suggest, represent a failure in conceptualisation.

Other age groups dealt with the problem of left-over objects differently. Each child in the youngest age group was left with objects that did not fit into other groups. These were formed into a group of their own, on the basis of all being 'odd shapes'. Adolescents, when faced with objects which did not readily fit into other groups, tended to expand their criteria to include a wider variety of concepts that would cover the remaining objects.

Adults appear to identify main criterial attributes without being influenced by the physical/perceptual properties of objects, whereas young children react, as Stones (1979) points out, to each specific object, not to the abstract properties that characterise a class of objects. Adolescents, on the other hand, seem to combine a more abstract properties with perceptual ones.

Concepts are built on experience and since adults have usually had greater experience with the use of objects, it seems logical that they would automatically focus on functional criteria.

Adolescents tended to be more flexible, rejecting concepts and selecting others on a 'trial-and-error' basis as they attempted to find the most satisfactory groupings.

The three age groups varied in the size of groups they formed, with adolescents using slightly smaller groups than adults, and younger children using considerably larger groups. These average group sizes mask the fact that both children and adults tended to form one or two quite large groups, along with (in the case of adults) up to three single ungrouped objects, whereas the adolescents were much more likely to evenly distribute objects in their groups.

This variable of group size has been referred to as 'conceptual differentiation' whereby a high level of conceptual differentiation results in a large number of categories. It seems possible that higher levels of conceptual differentiation may equate with higher cognitive complexity, although there appears to be no evidence to support this connection (Kagan & Kogan, 1970). It would, however, offer an explanation for the smaller number of groups used by younger children who do not possess the cognitive complexity of adolescents and young adults.

Relevance of findings for the teaching of concepts

It is clearly vitally important that teachers understand the different levels of thinking and understanding used by children and adolescents to ensure that there is no 'mismatch' in thinking between teacher and pupil when concepts are being learned (Stones, 1979, p.99).

Since younger children do not have the cognitive ability for abstraction which older children possess, it can be useful to use concrete or visual aids with this age group. Stones (1979, p.100-101) warns against too great a use of visual aids since the aim is to develop children's reasoning ability. Stones (1979, p.202) says that one of the most important considerations in teaching is how best to help the pupil to identify the crucial attributes of a concept. By understanding how younger children are influenced by the visual properties of an object, the teacher is able to allow for this in his or her teaching. This might involve controlling and varying the physical non-essential aspects of a concept such as size, colour and material (Stones, 1979, p.60), while at the same time pointing out that these perceptually dissimilar things are examples of the same concept. Stones (1979, p.95) suggests also that containers might be masked during conservation teaching to force children's attention away from the distracting perceptual aspect.

For adolescents, this study suggests that they draw on complex bodies of concepts. In teaching this age group, consideration should be given to using a questioning process which would help students to abstract the essential common properties (Stones, 1979, p.312).

There may also be implications for adult learning. Adult education teachers might encourage learners to expand their concepts, to draw upon a wider range of concepts in problem solving and to be more flexible in their thinking.


Although a small sample was used in this study and, as a result, the results must be viewed with caution, the study has nevertheless provided some interesting insights into concept development at various ages. In particular, this task shows that there are considerable individual differences in conceptualisation even within the same group, a fact of which teachers should always be aware.

There is clearly much to be learned about the different ways in which children, adolescents and adults think and learn. Future studies using a larger sample would supply further valuable information.


Bourne, L. (1971) 'Human Conceptual Behaviour' in J. Eliot (ed.), Human Development and Cognitive Processes, Holt, Rinehart and Winston: New York.

Bruner, S.J., Oliver, R.R., Greenfield, P.M. et al (1966) Studies in Cognitive Growth, John Wiley and Sons: New York.

Glass, A.L., Holyoak, K.J. & Santa, J.L. (1979) Cognition, Addison-Wesley: Massachusetts.

Kagan, J. & Kogan, N. (1970) 'Individual Variation in Cognitive Processes' in P.H. Mussen (ed.), Manual of Child Psychology, Vol.1, John Wiley and Sons: New York.

Stones, E. (1979) Psychology of Education: A Pedagogical Approach, Methuen: USA.

Wallach, M.A. & Kogan, N. (1965) Modes of Thinking in Young Children, Holt, Rinehart and Winston: New York.

Please cite as: Gilmore, L. (1990). Categorisation and concept development. Queensland Researcher, 6(2), 48-54. http://www.iier.org.au/qjer/qr6/gilmore.html

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Created 15 Oct 2006. Last revision: 15 Oct 2006.
URL: http://www.iier.org.au/qjer/qr6/gilmore.html