MIGRATION AND THE "INSTINCT" PROBLEM
To say that an animal performs an activity "instinctively" means that the performance of the activity, in all probability, mainly depends upon an activation of the animal's inherited equipment, i.e., the sensory, nervous, and motor structures of the species, more or less independently of individual experience. Migration and pecking as they occur in various birds are examples of the "basic activities" which result. In such activities, the function of learning is by no means excluded, but it is of secondary importance in determining the nature of the act.
Contrary to the belief of the traditional "instinct psychologists," an acceptable and useful explanation of a given "instinct" can be attempted only when we have gained an adequate knowledge of the essential causes of the activity in question and of the manner in which the causal factors, in a given environment, produce this activity in a given animal. We learn nothing about such behavior from statements such as "the chick possesses a pecking instinct," an interpretation which amounts to saying nothing more than "the chick pecks because it pecks." Similarly, to speak of an instinctive urge for pecking, migration, or any other observed activity really begs the question. The word "urge" has an appropriate psychological meaning and should not be misused. Unless a chick has pecked one or more times, to say that it possesses an "urge to peck" is a statement which seems actually incorrect. In any case, it leaves the problem unsolved, since the word "urge," like the word "instinct," is here merely a substitute for real knowledge of the causes of pecking.
Migration is one of the most typical "instinct" problems, and one which illustrates very satisfactorily the principal characteristics of such problems in higher animals. Furthermore, migration is a form of behavior which has long aroused much popular interest and which