I. INTRODUCTION 



The experiments in this monograph ' aim at an analysis of 

 typical mammalian behavior under conditions where the de- 

 termining stimulus is absent at the moment of response. Asso- 

 ciations were first set up between movements that led to food 

 and a light which might be in any one of three boxes. Controls 

 were used to make sure that the position of the light alone 

 determined the reactions of the subject. Tests were then in- 

 stituted in which the light was turned off before the reaction 

 was made. The subject thus had to respond in the absence of 

 the stimulus that hitherto had guided his reactions. 



The nature of the present experiment may be further set 

 forth by contrasting it with the following type of adjustment: 

 A cat watches for a mouse and sees it appear at an open hole. 

 The mouse vanishes before the cat can react, yet the cat goes 

 over to the hole. There can be no question here but that the 

 determining stimulus is absent at the moment of response, pro- 

 vided possible olfactory stimuli be neglected. Our experiment 

 differs from this in complexity. If there were three holes that 

 differed only in their several directions from the cat, and if in 

 the past the mouse had appeared an equal number of times in 

 all three holes, the conditions would be the same as in our tests. 

 A selection between the three holes would need to be made on 

 the basis of the immediately previous presence of the rat, if 

 a correct reaction were to occur. If an animal can manifest 

 behavior that does not lend itself to a "stimulus and response" 

 explanation, this is one type of situation in w^hich that behavior 

 should appear. That, in fact, it is the situation par excellence 

 for the eliciting of this behavior will, I believe, appear as this 

 monograph progresses. 



' Experimentation on the present problem was first begun in the University of 

 Chicago laboratory by a graduate student, W. R. Hough. The following year 

 the work was taken up and carried somewhat further by another student, H. B. 

 Reed. Both students worked with white rats. Although in each case the results 

 obtained were in strict harmony with those presented in this paper, in neither 

 case were they conclusive. The chief value of the work lay in its suggestiveness. 

 The apparatus used by Reed — Prob. Box D — is described below. The present 

 investigation was carried on in the same laboratory from October, 1910 to 

 April, 1912. 



