Heuristic is an important concept in psychology.  
People may use heuristics in some important judgments
and decisions.  Thus, it is important to define heuristic.  
What is an heuristic?  Below is a definition of heuristic
with respect to judgment and decision making:

Heuristic Definition:

A heuristic is a simple rule that is used in making
judgments and decisions.

Heuristic Examples:

 Bell and Loftus (1989) suggested that trivial persuasion
may reflect simple, general rules concerning  source
credibility.  Trivial persuasion is the persuasive effect of
minor or trivial details on decisions.  Bell and Loftus found
that mock jurors were influence by trivial details in
eyewitness testimony in a hypothetical court case.  This
could reflect a simple rule that reporting trivial details
reflects a good memory.

 Tversky and Kahneman (1974) provided information
about three heuristics in judgment.  One of these is the
availability heuristic.   Using this heuristic, someone
might estimate the frequency of people who are cat
owners based the ability to retrieve examples of people
who are cat owners.     


Bell, B. E., & Loftus, E. F. (1989).  Trivial persuasion
 in the courtroom:  The power of (a few) minor    
Journal of Personality and Social
, 56,669-679.
Tversky, A., & Kahneman, D.  (1974). Judgment under
 uncertainty:  Heuristics and biases.