NOTES 



THE ROLE OF THE EXPERIMENTER IN COMPARATIVE 



PSYCHOLOGY 



ROBERT M. YERKES 

 Harvard Psychological Laboratory 



In Comparative Psychology attention has recently been concentrated upon the 

 control of the experimental situation to the neglect of two other aspects of our 

 task which are equally worthy of study, — namely, the management of the subject 

 and the reliable recording of responses. Every psychological problem presents, 

 if attacked experimentally, these three technical demands: first, such control of 

 the objective situation as shall render it not only suitable for the solution of the 

 particular problem, but at the same time, highly controllable and describable; 

 second, such knowledge of the subject, human or infra-human, as shall enable the 

 experimenter to avoid unnaturalness, or otherwise unnecessary ill-adjustment of 

 subject to objective situation; and third, such provision for the recording of response 

 as shall provide wholly reliable and sufficiently detailed descriptions of the sub- 

 ject's behavior. 



By experience in working with various animals and with pathological human 

 subjects, I am convinced of the urgent need of attention to our methods of record- 

 ing reactions. We, at present, allow the experimenter too great range and place 

 upon him over-great responsibility. As observer, he is liable both to influence the 

 subject in his attempts to get data of reaction and, in turn, to be influenced, in his 

 descriptions of what he sees, by his unescapable tendencies to interpret. Quite 

 evidently, the ideal experiment is one in which the subject provides us a detailed 

 photographic record (or other form of graphic record) of its response. It is the 

 writer's belief that we should make systematic and persistent attempts to develop 

 recording devices which shall free us from the observational imprefections of the 

 experimenter. 



This means that our apparatus for use in Comparative Psychology must be 

 largely automatic or self-controlling over considerable periods of time, not only 

 with respect to the objective situation or setting in which the subject reacts, but 

 also with respect to the recording of the several important aspects of response. 

 We should devise types of recording mechanism which shall either operate auto- 

 matically or be operated by the subject rather than by the experimenter. This 

 would mean not the elimination of the observer but the freeing of his attention 

 f or those aspects of the total experiment which most urgently demand control. 



As an example of a practical recording device, I may mention that of the Hamil- 

 ton Quadruple Choice Apparatus which, in its latest improved form (thus far un- 

 described) permits the experimenter to confront his subject with a certain situation 

 and then leave that subject to work out a series of problems, its behavior in con- 

 nection with which is the while accurately recorded by a system of markers, elec- 

 trically actuated. 



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