THE RELATION OF STRENGTH OF STIMULUS 

 TO RAPIDITY OF HABIT-FORMATION 



BY 



ROBERT M. YERKES AND JOHN D. DODSON. 



{From the Harvard Psychological Laboratory) 

 With Five Figures. 



In connection with a study of various aspects of the modifiabihty 

 of behavior in the dancing mouse a need for definite knowledge 

 concerning the relation of strength of stimulus to rate of learning 

 arose. It was for the purpose of obtaining this knowledge that 

 we planned and executed the experiments which are now to be 

 described. Our work was greatly facilitated by the advice and 

 assistance of Doctor E. G. Martin, Professor G. W. Pierce, and 

 Professor A. E. Kennelly, and we desire to express here both our 

 indebtedness and our thanks for their generous services. 



The habit whose formation we attempted to study quantita- 

 tively, with respect to the strength of the stimulus which favored 

 its formation, may be described as the white-black discrimina- 

 tion habit. Of the mice which served as subjects in the investi- 

 gation it was demanded that they choose and enter one of two boxes 

 or passage-ways. One of the boxes was white; the other black. 

 No matter what their relative positions, the subject was required 

 to choose the white one. Attempts to enter the black box resulted 

 in the receipt of a disagreeable electric shock. It was our task 

 to discover (i) whether the strength of this electric stimulus influ- 

 ences the rapidity with which dancers acquire the habit of avoiding 

 the black passage-way, and if so, (2) what particular strength of 

 stimulus is most favorable to the acquisition of this habit. 



As a detailed account of the important features of the white- 

 black visual discrimination habit in the dancer has already been 

 published,^ a brief description of our method of experimentation 



' Yerkes, Robert M. The dancing mouse. New York: The Macmillan Company. See especi- 

 ally p. 92, et seq. 1908. 



