Heuristics

The study of induction spans a variety of methods and topics. In this article,
most of the consideration of induction involves cases in which people rely
on heuristics in their reasoning. Heuristics involve “rules of thumb” that
yield “ballpark” solutions that are approximately correct and can be applied
across a wide range of problems.
One common heuristic is representativeness, which is invoked in answering
the following questions: What is the probability that object A belongs to
class B, event A originates from process B, or that process B will generate
event A? The representativeness heuristic suggests that probabilities are
evaluated by the degree to which A is representative of B, that is, by the degree
to which A resembles B. If A is representative of B, the probability that
A originates from B is judged to be high; if A does not resemble B or is not
similar to B, the probability that A originates from B is judged to be low.
A second heuristic is availability, which is invoked in judgments of frequency.
Specifically, people assess the frequency of a class by the ease with
which instances of that class can be brought to mind. Factors that influence
the ability to think of instances of a class, such as recency, salience, number
of associations, and so forth, influence availability in such a way that certain
types of events (such as recent and salient) are more available. For example,
if several people one knows have been involved in car crashes recently, one’s
subjective probability of being in a car crash is increased.