A STUDY OF TRIAL AND ERROR REACTIONS 



IN MAMMALS 



By G. V. HAMILTON, M. D. 



Montecito, California 



THREE FIGURES 



I. Introduction; Description of Apparatus; Description of Method 33 



II. Description of Subjects 39 



III. Tabulation of Preliminary Analysis of Results 44 



IV. Determination of the Different Modes of Adjustment Manifested 48 



V. Interpretation of Results 56 



VI. Summary and Conclusions 63 



I. INTRODUCTION; DESCRIPTION OF APPARATUS; DESCRIPTION 



OF METHOD 



The literature of animal behavior contains considerable experi- 

 mentally obtained evidence that among the mammalia there are 

 marked differences of ability to profit by experience, but these 

 differences have been analysed almost exclusively in terms of 

 sensory equipment and of quantitative measurements of reac- 

 tion time and reactive errors. The trial and error mode of 

 adjustment has thus come to serve the student of behavior as 

 a conceptional unit in his analyses of mammalian reactions, 

 and has been dealt with as genetically variable only with refer- 

 ence to the degree of rapidity with which it leads to the formation 

 of associations appropriate to given situations, and to the elimi- 

 nation of useless activities. We speak of qualitatively different 

 instinctive adjustments, but not of qualitatively dift'erent " try- 

 try -again " (trial and error) efforts to meet a situation for which 

 there is no specifically appropriate instinct, no opportunity for 

 imitation of any kind, and no rational equipment. 



The present investigation seeks to collect facts of behavior 

 which may lend themselves to qualitative interpretations of 

 trial and error activities. In other words, it is concerned with 

 the following problem: What, if any, are the qualitative differ- 

 ences of reactive tendency that account for the fact that some mammals 

 learn slowly, and with many errors, to meet situations which their 

 fellows of superior age or race learn to meet quickly and with but 

 few errors? 



We cannot know how to attack this problem, nor specifically 

 what to look for, until we gain a general orientation concerning 



33 



