The causal version of the cab problem had the form of a stereotype: Green
drivers are dangerous. Stereotypes are statements about the group that
are (at least tentatively) accepted as facts about every member. Hely re
are two examples:
Most of the graduates of this inner-city school go to college.
Interest in cycling is widespread in France.These statements are readily interpreted as setting up a propensity in
individual members of the group, and they fit in a causal story. Many
graduates of this particular inner-city school are eager and able to go to
college, presumably because of some beneficial features of life in that
school. There are forces in French culture and social life that cause many
Frenchmen to take an interest in cycling. You will be reminded of these
facts when you think about the likelihood that a particular graduate of the
school will attend college, or when you wonder whether to bring up the Tour
de France in a conversation with a Frenchman you just met.
Stereotyping is a bad word in our culture, but in my usage it is neutral. One
of the basic characteristics of System 1 is that it represents categories as
norms and prototypical exemplars. This is how we think of horses,
refrigerators, and New York police officers; we hold in memory a
representation of one or more “normal” members of each of these
categories. When the categories are social, these representations are
called stereotypes. Some stereotypes are perniciously wrong, and hostile
stereotyping can have dreadful consequences, but the psychological facts
cannot be avoided: stereotypes, both correct and false, are how we think
of categories.
You may note the irony. In the context of the cab problem, the neglect of
base-rate information is a cognitive flaw, a failure of Bayesian reasoning,
and the reliance on causal base rates is desirable. Stereotyping the Green
drivers improves the accuracy of judgment. In other contexts, however,
such as hiring or profiling, there is a strong social norm against
stereotyping, which is also embedded in the law. This is as it should be. In
sensitive social contexts, we do not want to draw possibly erroneous
conclusions about the individual from the statistics of the group. We
consider it morally desirable for base rates to be treated as statistical facts
about the group rather than as presumptive facts about individuals. In other
words, we reject causal base rates.
The social norm against stereotyping, including the opposition to