Find over 25,000 psychological definitions


inclusive fitness

the reproductive success not only of an individual but also of all of that individual’s relatives in proportion to their coefficient of relatedness. In calculating estimates of reproductive success, it is assumed that parents, offspring, and siblings have an average of 50% of their genes in common; that grandparents and grand-offspring, as well as uncles or aunts and nieces or nephews, share 25% of genes; and that first cousins share 12.5% of genes.

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

December 19th 2024

Thanatos

Thanatos

n. the personification of death and the brother of Hypnos (sleep) in Greek mythology, whose name was chosen by Sigmund Freud to designate a theoretical set of strivings oriented toward the reduction of tension and life activity (see death instinct). In Freud’s dual instinct theory, Thanatos is seen as involved in a dialectic process with Eros (love), the striving toward sexuality, continued development, and heightened experience (see life instinct). See also nirvana principle.