Abstract
In the most inclusive sense, psychological mechanisms offer a type of causal explanation of mental states and behavior, often with reference to underlying processes, systems, activities, or entities. By postulating and investigating such mechanisms, researchers have sought explanations of a wide range of psychological phenomena. However, the concept has been deployed in dramatically different ways, with very different meanings, depending upon the particular school or tradition of psychology (and specific research program therein). In fact, usage has been so diverse as to defy easy categorization or definition. But a historical perspective, even if rather selective, can trace the broad outlines of the significance of psychological mechanisms for the study of the mind. Perhaps most notable is the role they have played in the psychoanalytic tradition; research efforts within behaviorism and cognitive science have also made liberal use of versions of the concept in their explanatory frameworks (for discussion of evolutionary psychology, see the entry “evolved psychological mechanisms”). Cutting across all of these traditions are several key themes relating to psychological mechanisms, including questions concerning the scope of the relevant causal claims, debates about causal determinism and regularity, and the unresolved relation between mind and body.