Categorization

When we think about the world one of the ways that we organize our thoughts is by putting them into categories. This process of developing categories is called concept formation. For example ‘animal’ is a concept that contains other sub-concepts and then further sub-concepts. We could divide animals into birds, fish, mammals, and so on. We could then divide birds into robins, sparrows, owls, and so on. When we apply our concepts we tend to use a set of defining features. For example we would classify the sparrow as a bird because it has a number of defining features that we associate with birds such as wings, feathers, beaks and flying. However, although we may have a set of defining features for a concept such as a bird we do not apply these rigidly. Penguins and ostriches are still classified as birds even though they do not fly.

Activity 1: Defining a simple concept

What makes a table a table? We all have a concept of what a table is and can easily recognize a table whether it is a dining table, garden table or coffee table. Take a moment to write a list of the defining features of a table.

Discussion

Most people who carry out this relatively simple task will tell you that a table has a flat surface, four legs to raise it off the ground and that you can put things on it. They may add other features such as it is an item of furniture or it is often but not always made of wood, but the first three features are the most frequent responses.

However look at the picture in Figure 1.

Figure 1. A non-typical table

This table does not have four legs but most of us would still recognize it as a table, as it has a flat surface that we can put things on.

Similarly our definition of a table as a piece of furniture with a flat surface with four legs could just as easily be applied to a stool.

So, while we would find it difficult to specify a way of distinguishing between a small occasional table and a stool we would not walk into someone’s living room and sit on their occasional table just because it shares some of the same features as a stool. So our concepts are not clearly defined and seem to depend on what we expect to do with an object rather than how we define them. You may have heard the phrase fuzzy concept which reflects our difficulty in providing precise definitions.

So, we recognize the object in Figure 1 as a table because we could use it to put things on such as a book, our drink or an ornament. The object in Figure 2 is a stool because we would sit on it. We typically group objects within the same category or concept if we do the same thing with them.

Over-generalization

We use concepts so automatically that we are rarely aware that we are using them. Perhaps it is easier to see this process in action when we observe children developing their thinking as they struggle to develop concepts. Children often make mistakes by over-generalizing a concept that they are trying to get to grips with. They may have developed a concept for a dog as an animal with hair, four legs and a tail, but then they may also apply this label to a cat or a sheep or even a horse. Similarly they may learn that the tall person with the deep voice is called Daddy and then may embarrassingly identify any passing man as Daddy.

Arguably, young children (up to about 3;06 years) also over-generalize language concepts. For example, we know that the irregular past tense of verbs is acquired before the regular past tense (see Language Delay). Having learned that the past tense can be signaled through the use of the bound morpheme –ed, the child tends to over generalize this new knowledge to all verbs, regular or irregular. This leads to constructions such as daddy goed, mum buyed and Sarah eated.

Memory Tests

It may become evident how much we use concepts if we look at a few memory tests. Try the first test for yourself in the activity below.

Activity 2: A memory test

Read once through the list of words below trying to remember them. Then write down as many words as you can remember. When you have done this, read the discussion.

• Bed
• Peach
• Hat
• Armchair
• Daffodil
• Shirt
• Rose
• Lemon
• Sock
• Daisy
• Strawberry
• Table
• Buttercup
• Apple
• Sideboard
• Trousers

Discussion

Now that you have written all the words down that you can recall, let us see if you can remember any more words with the help of some cues. The list contains items belonging to the following categories:

• furniture
• fruit
• clothing
• flowers

Have the cues helped you remember any more words?

Have a look at your first try at recalling the words. Did you realize that the words belonged to categories and did you recall them in category clusters?

If possible, try this out on some other people and compare their results with yours.

This test is a simplified version of an experiment by Weston Bousfield (1953). Bousfield asked participants to learn a list of 60 words that could be divided into four categories. Though the words were presented in a random order, the participants tended to remember them in groups which belonged to the same category, so if they remembered apple, then they would remember peach, lemon and strawberry.

In our version of the experiment you were also asked to have a second go at recalling the words after you had been given the category headings. Most participants in these types of experiments find that although they think they have recalled all the words they will be able to remember, they can actually access more words once they have been given category headings as cues.

This illustrates that this information must have been available but without the cue they could not access it. When we try to recall information that has been organized, it seems each bit of the information cues the next bit because we have it stored in an organized rather than haphazard fashion.

Some research from George Mandler (1967) suggests that by organizing information we learn it even though we are not making any effort to memorize it. Mandler carried out an experiment where two groups of participants were given a pack of 100 cards each. Each card had a word printed on it. Both groups of participants were told to sort the cards into groups. They were allowed to have several tries at sorting the cards. The only difference between the two groups of participants was that members of the first group were told to try and memorize the words on the cards while they were sorting them but members of the other group were only told to sort the cards. When both groups were later tested by being asked to write down all the words they could remember, the group which was only told to sort the words remembered as many words as the group which was told to sort and memorize the words.

Activity 3: Identifying variables

In the Mandler experiment can you identify the following variables?

1. the independent variable
2. the dependent variable

Discussion

1. The independent variable is the variable that the experimenter manipulates, so this is the instruction to try and memorize the words which was given to one group only.
2. The dependent variable is the number of words recalled.

Mind mapping

You may rightly argue that being able to remember lists of words in category groups is not a particularly useful skill for everyday life. However the principle of organizing information so that it is grouped with related items can be applied to many activities (like reading this article). You may be aware of mind mapping, which is simply a way of organizing information so you can see which items go together and how they are related to other items.

Another way of organizing our thoughts which is very similar to concept formation but is more extensive, is using schemas.

References

Bousfield, W. A. (1953) ‘The occurrence of clustering in the recall of randomly arranged associates’, Journal of General Psychology, vol. 49, pp. 229–40, cited in Gross, R. (1996) Psychology: The Science of Mind and Behaviour, London, Hodder and Stoughton Educational.

Mandler, G. (1967) ‘Organization and memory’ in Spence, K. W. and Spence, J. T. (eds) ‘The Psychology of Learning and Motivation: Advances in Research and Theory’, New York, Academic Press. Reprinted in Bower, G. H. (ed.) (1977) Human Memory: Basic Processes, New York, Academic Press.

Acknowledgement

[Information last accessed: 27 July 2017]

This article is adapted from ‘Starting with psychology’. An OpenLearn (http://www.open.edu/openlearn/) chunk reworked by permission of The Open University copyright © 2016 – made available under the terms of the Creative Commons Licence v4.0 http://creativecommons.org/licenses/by-nc-sa/4.0/deed.en_GB. As such, it is also made available under the same licence agreement.