THE NUMBER AND VARIETY OF MAN'S INSTINCTS. Various attempts have been made, notably by such men as James, McDougall, and Thorndike, to enumerate and classify the tendencies with which man is at birth endowed, or which, like the sex instinct, make their appearance at a certain stage in biological growth, regardless of the particular training to which the individual has been subjected. Earlier classifications were inclined to speak of instincts as very general and as half consciously purposeful in character. Thus it is still popularly customary to speak of the "instinct of self-preservation," the "instinct of hunger," and the "parental instinct." The tendency of present-day psychology is to note just what responses take place in given specific situations. As a result of such observation, particularly by such biologists as Watson and Jennings,[1] instincts have come to be regarded not as general and purposive but as specific and automatic. Thus it is no instinct of self-preservation that drives the child to blink its eyes at a blinding flash of light; it is solely and simply the very direct and immediate tendency to blink its eyes in just that way whenever such a phenomenon occurs. It is no deliberate intent to inhale the oxygen necessary to the sustenance of life that causes us to breathe. No more is it a conscious plan to provide the organism with nourishment that prompts us to eat our breakfast in the morning; it is simply the immediate and irresistible enticement of food after a night's fast. Not a deliberate motive of maternity prompts the mother to caress and care for her baby, but an inevitable and almost invincible tendency to "cuddle it when it cries, smile when it smiles, fondle it and coo to it in turn." [Footnote 1: Watson: _Behavior_. H. S. Jennings: _Behavior of the Lower Organisms_.] In the last few years, as a result of the observation of animals under laboratory conditions, there has been increasing evidence of a large number of specific tendencies to act in specific ways, in response to specific given stimuli. As no stimuli are ever quite alike, and no animal organism is ever in exactly the same physico-chemical condition at two different times, there are slight but negligible differences in response. Allowing for these, animals may be said to be equipped with a wide variety of tendencies to do precisely the same things under recurrent identical circumstances. The aim of the experimental psychologist is to discover just what actions occur when an animal is placed in any given circumstances, precisely as the chemist notes what reaction occurs when two chemicals are combined.