Xref: utzoo comp.ai:3075 talk.philosophy.misc:1823 sci.lang:3922 Path: utzoo!attcan!uunet!lll-winken!ames!ucsd!cogsci!zhang From: zhang@cogsci.ucsd.EDU (Jiajie Zhang) Newsgroups: comp.ai,talk.philosophy.misc,sci.lang Subject: Re: Categorization Message-ID: <687@cogsci.ucsd.EDU> Date: 13 Jan 89 07:58:21 GMT References: <681@cogsci.ucsd.EDU> <2959@uhccux.uhcc.hawaii.edu> Organization: Institute for Cognitive Science, UC San Diego Lines: 86 In article , harnad@elbereth.rutgers.edu (Stevan Harnad) writes: > The problem is that this kind of research and this kind of conclusion > simply changes the subject: Instead of trying to find (C) the > representation that will allow us to perform X/non-X categorization > in the myriad cases where we can indeed do it in a reliable, all-or-none > fashion, it turns instead to (T) judgments of typicality and to > introspections about how we categorize, and then offers T as if it > were the mechanism for C, whereas T simply PRESUPPOSES a mechanism for > C, without specifying it or even realizing that the question has been > begged! Worse yet, a T-mechanism is put forward as a C-mechanism, a > job it certainly can't do! I agree that judgements of typicality can't provide us much information about the underlying mechanism of categorization. Prototypical effects are just effects, phenomena, and nothing more. They are just the outputs of some internal mechanisms underlying categorization. Early-Rosch did construct a prototype *theory*, which was intended to be a theory of the mechanism of categorization. However, late-Rosch gave up this kind of theory and only claimed that prototypical effect was just effect, not theory. This is an important point, and it was, for example, reiterated by Lakoff in his book. Though prototype *theory* didn't stand very long, the effect or phenomenon of prototypicality in categorization is real. Prototypical effect should be served as a constraint in the construction of a categorization theory, and any theory of categorization, if there is one, should be capable of explaining prototypical effect. > What should be apparent from this summary is that none of the > conclusions were based on examining categorization itself -- i.e., our > ability to categorize an X as an X and a non-X as a non-X for all > those X's with which we can demonstrably do this in a reliable, > successful, all-or-none fashion. I think our ability to perform categorization is just one of several important aspects of categorization. I think the following aspects are also important for the study of categorization. (1) Descriptive analyses of categories. These include intra- and inter-relationship of categories, characteristics of a category, taxonomy, etc. For example, biological taxonomy, Frank Keil's ontological categories. (2) Internal representations of categories. There are two parts: structure and process. Classical view, prototypical view, and examplar view are among many of the traditional approaches which tried to give a theory of how categories are represented in the mind. Lakoff's ICM is one of several recent approaches. Connectionism, in my opinion, might be the best tool (so far) to study categorization, though there hasn't been a connectionist theory of categorization yet. A theory of categorization should not only answer the question of what are the structures of internal representation of categories but also the question of HOW human beings actually DO the categorization. It should also be able to explain empirical data, such as prototypical effect. (3) Origin of categories, both ontogenetically and phylogenetically. Children's learning of categories and the evolution of categories are to some extent similar, but the difference between them is more important. Do categories exist objectively out there and wait for our human beings to find the regularities and pick them up? To what extent are categories artificial, that is, to what extent do human beings impose artificial categories on the nature? Learning categories through schooling is different from that through discovering, and that through creating. (4) Why do human beings categorize things? I think this might be related to what Harnad called miscategorization. Personally, I think this is a question about cognitive cost. (5) Borrowing from linguistics: relation between performance and competence of categorization, if this distinction makes any sense at all. > The ongoing rounds of criticism and > counter-criticism that have been set off by the Roschian research (to > which Zhang alludes at the end of the passage I quoted) are, in my > view, simply symptoms of the incoherence of the views that set this > whole bandwagon rolling in the first place. Prototypical effect is real. I don't think a theory which ignores prototypical effect is a reasonable and complete theory for categorization.