Radial categories as a further source of typicality effects
Lakoff proposes that the cluster model for MOTHER and the metonymic HOUSE WIFE-MOTHER stereotype taken together contribute to a composite prototype for MOTHER: a prototype derived from two models. This prototype provides rep resentative structure for the category. For example, the composite prototype for the category MOTHER includes a female who gave birth to the child, was sup plier of 50 per cent of the genetic material, stayed at home in order to nurture the child, is married to the child’s father, is one generation older than the child and is also the child’s legal guardian. In other words, the composite prototype draws upon information from the BIRTH MODEL, the GENETIC MODEL, the NUR TURANCE MODEL, the MARITAL MODEL, the GENEALOGICAL MODEL and the HOUSEWIFE MODEL, which is asocial stereotype. This type of prototype is an idealisation which provides schematic information. Importantly, further models can be derived from this composite prototype. These models include ADOPTIVE MOTHER, FOSTER MOTHER, BIRTH MOTHER and SURROGATE MOTHER. As Lakoff points out:
These variants are not generated from the central model by general rules; instead, they are extended by convention and must be learned one by one. But the extensions are by no means random. The central model determines the possibilities for extensions, together with the possible relations between the central model and the extension models. (Lakoff 1987: 91)
A composite prototype and extensions of this kind are modelled in terms of a radiating lattice structure. The composite prototype is positioned centrally with other subcategories represented as extending from the central case (see Figure 8.2).
Crucially, the non-central cases in such radial categories are not strictly predictable from the central case but are cultural products. For instance, the subcategories of MOTHER listed below are all understood in terms of how they diverge from the central case.
1. STEPMOTHER– married to the father but didn’t supply genetic material or give birth.
2. ADOPTIVE MOTHER– provides nurturance and is the legal guardian.
3. BIRTH MOTHER– gave birth and supplied genetic material but put the child up for adoption hence does not nurture the child and has no legal responsibilities.
4. FOSTER MOTHER– charged by the state to nurture the child but is not the child’s legal guardian.
5. SURROGATE MOTHER– gives birth to the child, typically does not supply the genetic material and has no other obligations to the child.
Thus radial categories of this kind provide a fourth way in which typicality effects can arise. These effects occur when the subcategories are seen to deviate from the composite prototype. Moreover, as particular categories can become more conventionalised than others, different subcategories in a radial category can develop different degrees of prototypicality.
Importantly, radial categories are not ‘generators’. The central case does not productively generate new subcategories of the MOTHER category. While the subcategories are motivated in the sense that they are licensed by the proto type, this is a consequence of our cultural experience. For instance, the sub category SURROGATE MOTHER is a consequence of recent achievements in medicine and cultural trends and has appeared in the second half of the twentieth century. In sum, radial categories are motivated, but knowing a prototype does not predict what subcategories will become conventionally adopted in the culture. We will have more to say about radial categories and how they apply to word meaning in Chapter 11.
To summarise this section, we have seen that there are four ways in which Lakoff accounts for typicality effects. The first kind of typicality effect arises from mismatches between ICMs. The second kind of typicality effect arises from more complex cognitive models which Lakoff calls cluster models. These consist of a number of distinct subcategory models. Typicality effects occur when one subcategory is deemed to be more salient than the others. The third kind of typicality effect relates to metonymic ICMs. These are essentially exemplar-based cognitive models in which a particular member of a given category stands for the category as a whole. Assessed with respect to the metonymic models, other members of a category may be evaluated as being atypical. The fourth kind of typicality effect arises from radial categories, in which members of a radial category exhibit degrees of typicality depending on how close to the composite prototype they are.
