Thinking and Deciding

34 THE STUDY OF THINKING
The second problem with attempting to apply normative models directly is that
we sometimes may do better, according to these models, by aiming at something
else. For example, we shall see that people tend to be biased toward possibilities
they already favor. This kind of bias may affect judgments of probability, which may
be part of the attempt to apply a normative model of belief. So it may be necessary
to bend over backward to avoid such effects.
In short, normative models tell us how to evaluate judgments and decisions in
terms of their departure from an ideal standard. Descriptive models specify what
people in a particular culture actually do and how they deviate from the normative
models. Prescriptive models are designs or inventions, whose purpose is to bring the
results of actual thinking into closer conformity to the normative model. If prescriptive
recommendations derived in this way are successful, the study of thinking can
help people to become better thinkers.
Methods for empirical research
The development of descriptive models is the business of psychological research. A
great variety of methods can help us in this task. Some involve observation of people
(or animals) in their usual activities. Other methods involve construction of artificial
situations, or experiments.
Observation
When we observe, we collect data but do not intervene, except insofar as necessary to
get the data. Sometimes we can get interesting data literally by observing and recording
what people do in a natural setting. Keren and Wagenaar (1985), for example,
studied gambling behavior by observing blackjack players in an Amsterdam casino
over a period of several months, recording every play of every game. Observations
of behavior in real-life situations do not encounter the problems that may result from
subjects trying to please a researcher; however, there are other problems. Goals in
the real world are often complex, and it is difficult to “purify” the situation so as
to determine how a subject would pursue a single goal. For example, a subject in a
hypothetical gambling experiment can be instructed to imagine that his goal is to win
as much as he can, but Keren and Wagenaar (1985) found that in real life gamblers
were often as concerned with making the game interesting as with winning.
Process tracing
Many methods attempt to describe thinking by tracing the process of thinking as it
occurs. These methods are not concerned with the subject’s conclusion, but with
how the conclusion was reached, that is, the steps or “moves” that led to it. Ideally,
it would be nice to have a mind-reading machine that displays the subject’s thoughts