The platysma changes the facial expression which plays an important role in human social behavior. In elderly people â when the skin increasingly loses its elasticity â both inner faces of the platysma form two longitudinal wrinkles on the neck.
Biological psychology is a branch of psychology that studies the physiological causes of behavior. This field is sometimes referred to as behavioral neuroscience or biopsychology.
The biological perspective is just one school of thought in psychology. Other methods, like humanism or cognitive psychology, focus more on a person's desires and state of mind rather than biological causes for behavior.