THORNDIKE'S "ANIMAL INTELLIGENCE" 1 



HARVEY CARR 



The University of Chicago 



Professor Thorndike's series of experimental papers, repub- 

 lished in this volume, constitute a conspicuous landmark in 

 the development of comparative psychology. A review, thirteen 

 years after the appearance of the first paper, can pretend to be 

 little else than an appreciation in the light of subsequent pro- 

 gress, (i) The existence of the trial and error method of learn- 

 ing was demonstrated in fishes, chicks, cats, dogs, and monkeys. 

 The random activities are an expression of the animal's innate 

 and acquired nature, and any problem must be adapted to this 

 nature. Motives of hunger, release from confinement, the 

 social instinct, and preference for shade were utilized. Sub- 

 sequent work has extended these tests and results practically 

 throughout the zoological scale. (2) The analysis of imitation is 

 excellent. The methods are those in use today. The results 

 were negative for all animals studied. The conclusions as to 

 inferential imitation have been substantiated by subsequent 

 work. The author admits the possibility of other forms of 

 imitation, and his statement that no influence upon conduct 

 was evident in his tests must be interpreted in the light of the 

 fact that his interest in inferential imitation would lead him to 

 overlook slight influences of an instinctive and social nature. 

 The tests were not always sufficiently controlled, but this defect 

 was explicitly recognized, a statement which can not be made 

 of some subsequent work. (3) The experiments on tuition 

 have not stood the test of repetition and criticism. Again, the 

 author was interested in the influence of ideas, and in this 

 respect his conclusions seem valid. (4) Transference of training 

 to similar problems was noted, but not much of the phenomenon 

 is understood at present. The interpretation of the doctrine of 

 recepts is probably the conventional one. (5) Difference of 

 retentive ability was studied. Such tests have been duplicated, 



1 Thorndike, Edward L. Animal Intelligence. New York, The Macmillan Com- 

 pany, 1911, pp. viii+297. This is the third volume of the "Animal Behavior 

 Series." 



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