The heavy reliance on eyewitness identification suggests that such identifications are mechanical reproductions of an objective reality. Research in general and social psychology, however, indicates that perceptual and memory processes do not yield photographic or exact records of events. Research has found that memory, cognition, and information processing are active rather than passive abilities that involve the organization of discrete elements of a situation. Individual factors affecting perceptions of persons and events are emotional and motivational states, prior experience, and stereotypes and prejudice. The social-psychological context of eyewitness identification at a lineup bears the particular distorting influences of social conformity, the legitimacy of authority, evaluation apprehension and expectancy, and self-persuasion. Contemporary research in legal psychology indicates that the manner of questioning of an eyewitness affects the nature of the information provided, suggesting that investigatory procedures may influence witnesses in subtle and unintentional ways. Other factors found to influence eyewitness identifications are the type of identification process, the timing of the identification, bias in explicit instructions given to the eyewitness, and nonverbal communication of expectancies from the presiding police officer. Every effort should be made to identify and reduce or eliminate those contextual influences that would tend to distort eyewitness identifications. A total of 142 references are provided.