A reference to the study of the mind in all of its relationships, normal and abnormal.

An ongoing behavior or mental activity that contributes to some adaptation of the organism as a whole to the conditions of its surroundings.

It is analogous to the physiologic function of an organ; such as, the secretion of thyroxin by the thyroid gland; therefore, learning and the operation of the sensory processes underlying distance perception are held to be psychological functions of the cerebral cortex