Cognitive Representation of Semantic Categories

n her 1975 paper, Cognitive Representation of Semantic Categories (J Experimental Psychology v. 104:192-233), Eleanor Rosch asked 200 American college students to rank, on a scale of 1 to 7, whether they regarded the following items as a good example of the category furniture. The resulting ranks are as follows:

1 chair
1 sofa
3 couch
3 table
5 easy chair
6 dresser
6 rocking chair
8 coffee table
9 rocker
10 love seat
11 chest of drawers
12 desk
13 bed
...
22 bookcase
27 cabinet
29 bench
31 lamp
32 stool
35 piano
41 mirror
42 tv
44 shelf
45 rug
46 pillow
47 wastebasket
49 sewing machine
50 stove
54 refrigerator
60 telephone

While one may differ from this list in terms of cultural specifics, the point is that such a graded categorization is likely to be present in all cultures. Further evidence that some members of a category are more privileged than others came from experiments involving:

1. Response Times: in which queries involving a prototypical members (e.g. is a robin a bird) elicited faster response times than for non-prototypical members.

2. Priming: When primed with the higher-level (superordinate) category, subjects were faster in identifying if two words are the same. Thus, after flashing furniture, the equivalence of chair-chair is detected more rapidly than stove-stove.

3. Exemplars: When asked to name a few exemplars, the more prototypical items came up more frequently.

Subsequent to Rosch's work, prototype effects have been investigated widely in areas such as colour cognition (Brent Berlin and Paul Kay, 1969), and also for more abstract notions. Subjects may be asked, e.g. "to what degree is this narrative an instance of telling a lie?" [Coleman/Kay:1981]. Similarly work has been done on actions (verbs like look, kill, speak, walk [Pulman:83]), adjectives like "tall" [Dirven/Taylor:88], etc.

Another aspect in which Prototype Theory departs from traditional Aristotelian categorization is that there do not appear to be natural kind categories (bird, dog) vs. artefacts (toys, vehicles).