Saturday, February 12, 2005

Categorical Beginnings

It's never easy to begin a paper, especially a science paper. You want to start out general enough that people will understand the general importance of the paper, and you want to capture the attention of your readers, but you're bound by the principles of scientific writing, which can be pretty restricting. I myself have written entire papers before even attempting the first paragraph. There is one area of cognitive psychology, though, in which starting papers seems to be even more difficult than usual. This is the only explanation I can think of for the continual rehashing of the same beginning for at least 4 decades. The area? The study of concepts and categorization.

In order to demonstrate what I mean, here are a few examples of actual opening sentences and paragraphs from papers on categorization:
The world consists of a virtually infinite number of discriminably different stimuli. One of the most basic functions of all organisms is the cutting up of the environment into classifications by which nonidentical stimuli can be treated as equivalent.
-From Rosch, E., Mervis, C.B., Gray, W., Johnson, D., & Boyes-Braem, P. (1976). Basic objects in natural categories. Cognitive Psychology, 8, 382-439, which, by the way, would make a good addition to the list.

One of the major components of cognitive behavior concerns abstracting rules and forming concepts. Our entire system of naming objects and events, talking about them, and interacting with them presupposes the ability to group experiences into appropriate classes. Young children learn to tell the difference between dogs and cats, between clocks and fans, and between stars and street lights.
-From Medin, D.L., & Schaffer, M.M. (1978). Context theory of classification learning. Psychological Review, 85, 207-238, which is another classic.

Categorization is one of the most basic cognitive functions. Why is the ability to categorize events or objects important to an organism? An obvious answer to this question is that categories are important because they often have functional significance for the organism. Another familiar answer is that grouping objects into categories allows for efficient storage of information about these groups of objects.
- From Corter, J.E., & Gluck, M.A. (1992). Explaining basic categories: Feature predictability and information. Psychological Bulletin, 111, 291-303.

Is the plant edible or poisonous? Is the person friend or foe? Was the sound made by a predator or by the wind? All organisms assign objects and events in the environment to separate classes or categories. This allows them to respond differently, for example, to nutrients and poisons, and to predators and pray. Any species that lacked this ability would quickly become extinct. [Here they actually includes a citation! To a previous paper by the first author.]
- From Ashby, F. G., & Ell, S. W. (2001). The neurobiology of category learning. Trends in Cognitive Sciences, 5, 204-210.

Beachcombers categorize flotsam as man or fish. Players of 20 questions categorize things as animal, vegetable or mineral. Guards categorize approachers as friend or foe. Bystanders categorize flying objects: ‘Look, up in the sky! It’s a bird; it’s a plane! No, it’s Superman!’ Categorization permeates cognition in myriad protean variations.
- From Kruschke, J.K. (2005). Category Learning. In: K. Lamberts and R. L. Goldstone (eds.), The Handbook of Cognition, Ch. 7, pp. 183-201. London: Sage. This one actually begins with a quote from The Tempest, an indication that the author may have struggled even more than is usual, to come up with an opening.
So, you get the point. Categorization is one of the basic functions, major components, and adaptive necessities of cognition, and it "permeates cognition in myriad protean variations." I'm particularly impressed with the Ashby and Ell opening, which includes a citation for its view that categorization is important. It's not even a citation that begins with "e.g." I mean, given the frequency with which that same point is made in the opening of papers on categorization, you'd think a citation for that view would include a tediously long list of papers, or at least suggest that the paper cited is just one example of many that begin that way.

I wish these five examples were unusual, but they are not. Every year, at least two or three papers on categorization begin with a similar cookie-cutter opening paragraph. At this point, do we really need to be convinced that categorization is important? I'm pretty sure Aristotle taught us this more than two thousand years ago. The only explanation I can come up with for these is that it's just really hard to start a paper on categorization. With a literature spanning two millennia, it must be tough to come up with something original.