246 • CHAPTER 9 Knowledge
response to a stimulus if it contains some of the information needed to respond to
the stimulus. This apparently occurs when the good greens are presented in the test
(Figure 9.7b), but not when the poor greens are presented (Figure 9.7c). Thus, the
results of the priming experiments support the idea that participants create images of
good prototypes in response to color names. Table 9.1 summarizes the various ways,
previously discussed, that prototypicality affects behavior.
The prototype approach to categorization, and in particular Rosch’s pioneering
research, represented a great advance over the defi nitional approach because it pro-
vided a wealth of experimental evidence that all items within a category are not the
same. Another approach to categorization, called the exemplar approach, also takes
into account the wide variation among items that belong to a particular category.THE EXEMPLAR APPROACH: THINKING ABOUT EXAMPLES
The exemplar approach to categorization, like the prototype approach, involves deter-
mining whether an object is similar to a standard object. However, whereas the stan-
dard for the prototype approach is a single “average” member of the category, the
standard for the exemplar approach involves many examples, each one called an exem-
plar. Exemplars are actual members of the category that a person has encountered in
the past. Thus, if a person has encountered sparrows, robins, and blue jays in the past,
each of these would be an exemplar for the category “birds.”
The exemplar approach can explain many of Rosch’s results, which were used to
support the prototype approach. For example, the exemplar approach explains the
typicality effect (in which reaction times on the sentence verifi cation task are faster for
better examples of a category than for poorer examples) by proposing that objects that
are like more of the exemplars are classifi ed faster. Thus, a sparrow is similar to many
exemplars, so it is classifi ed faster than a penguin, which is similar to few exemplars.
This is basically the same as the idea of family resemblance, described for prototypes,
that states that “better” objects will have higher family resemblance.WHICH APPROACH WORKS BETTER:
PROTOTYPES OR EXEMPLARS?
Which approach—prototypes or exemplars—provides a better description of how
people use categories? One advantage of the exemplar approach is that by using real
examples, it can more easily take into account atypical cases such as fl ightless birds.
Rather than comparing a penguin to an “average” bird, we remember that there are
some birds that don’t fl y. This ability to take into account individual cases means that
the exemplar approach doesn’t discard information that might be useful later. Thus,TABLE 9.1 Some Eff ects of PrototypicalityEff ect Description Experimental ResultFamily resemblance Things in a category resemble each
other in a number of ways.Higher ratings for high prototypical items
when people rate how “good” a member
of the category it is (Rosch, 1975).
Typicality People react rapidly to members of
a category that are “typical” of the
category.Faster reaction time to statements like
“A _____ is a bird” for high-prototypical
items (like robin) than for low-prototypical
items (like ostrich) (Smith et al., 1974).
Naming People are more likely to list some
objects than others when asked to
name objects in a category.High-prototypical items are named fi rst
when people list examples of a category
(Mervis et al., 1976).
Priming Presentation of one stimulus aff ects
responses to a stimulus that follows.Faster same–diff erent color judgments for
high-prototypical items (Rosch, 1975b).Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.