i6o THE POPULAR SCIENCE MONTHLY. 



SOME HUMAN INSTINCTS. 



By WILLIAM JAMES, 



PBOFLSSOR OF PHILOSOPHY IN HARVARD COLLEGE. 



IT is generally considered that a cardinal differentia of the human 

 race is its poor endowment in the way of instincts. Brutes need 

 instincts, it is supposed, because they have no reason. But man, with 

 his reason, can do without instincts. " Instinctive actions," says Pro- 

 fessor Preyer, in his careful little work, " Die Seele des Kindes," "are 

 in man few in number, and, apart from those connected with the sexual 

 passion, difficult to recognize after early youth is past. So much the 

 more attention," he adds, " should science pay to the instinctive actions 

 of young children." 



I believe this doctrine to be a great mistake. Instead of having 

 fewer, man has more instincts than any other mammal. He has so 

 many that they bar one another's path, and produce an indeterminate- 

 ness of action in him, supposed to be incompatible with that automatic 

 uniformity which, according to popular belief, characterizes all instinct- 

 ive performances. Popular belief is here in error. The more care- 

 fully instincts have been studied of late years, and the more clearly 

 their mechanism has been laid bare, the more evident has it become 

 that their effects are liable to be modified by various conditions. In- 

 stincts are due, at bottom, to the organization in the nerve-centers of 

 certain paths of discharge, or reflex-arcs, as they are technically called. 

 The disturbance produced in the way of sound, light, or other sensible 

 emanation, by some object in the environment, runs in at an animal's 

 senses, and then out through his muscles. Each special sort of dis- 

 turbance or stimulus affects a special set of muscles, and makes the 

 animal act in a special way, he knows not why, except that it seems 

 the only natural way to act at the moment. Witness the fear of a 

 natural enemy, the love of the opposite sex, the pursuit of a natural 

 prey. Some of these reflex-arcs are transient. Some of the environ- 

 ing objects stimulate more than one arc at once (as when the presence 

 of a strange dog awakens timorous, pugnacious, and sociable move- 

 ments, all at the same time, in another dog), and then small accidents 

 determine the resultant path of discharge. Finally, habits are formed 

 of reacting on one particular object of a kind, and inhibit the applica- 

 tion of the instinct to other individuals (limitation of the sexual in- 

 stinct to one mate, etc.). In an article published elsewhere,* I have 

 tried to trace these complications and variations, and to show that the 

 presence of too many instincts in a creature, some of them transient, 

 some of them tending in opposite ways, some of them inhibited in 

 their application by the habits earliest formed, must needs produce a 



* "Scribner's Magazine," March, 1887. 



