An evolutionary function of the depressive reaction: the cognitive map hypothesis

Existing hypotheses for an evolutionary function of depression are insufficient, primarily because they fail to show convincingly the advantages that might compensate for the high evolutionary costs of its features, such as general passivity, decreased appetite and sex drive.In this article, it is shown that depression may have the function of motivating a period of reduced activity after a major loss. It thus allows for time out to update the cognitive structures for altered circumstances, and avoids dangerous actions based on the use of inadequate cognitive maps. This cognitive map hypothesis provides a viable evolutionary explanation for the high incidence of depression reaction, in spite of its apparently unfavorable characteristics. The article discusses how this hypothesis may also shed light on the occurrence of clinical depression, proposing that it is caused by a failure to update complex conceptual cognitive structures. Finally, recommendations for the treatment of depression that derive from this hypothesis are presented.