Categorisation
An important recent finding in cognitive psychology is that categorisation is not criterial. This means that it is not an ‘all-or-nothing’ affair. Instead, human categories often appear to be fuzzy in nature, with some members of a category appearing to be more central and others more peripheral. Moreover, degree of centrality is often a function of the way we interact with a particular category at any given time. By way of illustration, consider the images in Figure 2.1. It is likely that speakers of English would select the first image 2.1(a) as being more representative of the category CUP than image 2.1(e). However, when drinking from the container in 2.1(e), a speaker might refer to it as a cup. On another occasion, perhaps when using a spoon to eat soup from the same container, the same speaker might describe it as a bowl. This illustrates that not only is categorisation fuzzy (for example, when does a cup become a bowl?), but also our interaction with a particular entity can influence how we categorise it.
Although the category members in Figure 2.1 may be rated as being more or less representative of the category CUP, each of the members appears to resemble others in a variety of ways, despite the fact that there may not be a single way in which all the members resemble each other. For instance, while the cup in 2.1(a) has a handle and a saucer and is used for drinking beverages like tea or coffee, the ‘cup’ in 2.1(d) does not have a handle, nor is it likely to be used for hot beverages like tea or coffee; instead, this cup is more likely to contain drinks like wine. Similarly, while the ‘cup’ in 2.1(e) might be categorised as a ‘bowl’ when we use a spoon to ‘eat’ from it, when we hold the ‘bowl’ to our lips and drink soup from it, we might be more inclined to think of it as a ‘cup’. Hence, although the ‘cups’ in Figure 2.1 vary in terms of how representative they are, they are clearly related to one another. Categories that exhibit degrees of centrality, with some members being more or less like other members of a category rather than sharing a single defining trait, are said to exhibit family resemblance.
However, fuzziness and family resemblance are not just features that apply to physical objects like cups; these features apply to linguistic categories like morphemes and words too. Moreover, category-structuring principles of this kind are not restricted to specific kinds of linguistic knowledge but apply across the board. In other words, linguistic categories – whether they relate to phonology, syntax or morphology – all appear to exhibit these phenomena. Formal approaches to linguistics have tended towards the view that a particular category exhibits uniform behaviour which characterises the category. As we will see, however, linguistic categories, despite being related, often do not behave in a uniform way. Instead, they reveal themselves to contain members that exhibit quite divergent behaviour. In this sense, linguistic categories exhibit fuzziness and family resemblance. We illustrate this below – based on discussion in Taylor (2003) – with one example from each of the following areas: morphology, syntax and phonology.
