Noun
(psychology, biology) The study of the biological basis for cognition and other mental processes.
(psychology) The branch of psychology that interprets psychological phenomena in terms of adaptation to biological, environmental, etc. factors.
Source: en.wiktionary.orgKersten Jacobson Biehn, "Psychobiology, Sex Research and Chimpanzees: Philanthropic Foundation Support for the Behavioral Sciences at Yale University, 1923–41," History of the Human Sciences 2008 21(2): 21–43, Old Brick Row in 1807. Source: Internet
Wilson, G., & Q. Rahman, Born Gay: The Psychobiology of Human Sex Orientation, op. cit. Source: Internet