J.— PSYCHOLOGY. 195 



it has exalted the principle of ' conditioned reflex ' into an all-embracing 

 explanation, though many of the problems of human response concern the 

 emergence of new effector functions and conditioned reflex has nothing 

 to do with this ; and though conditioning at the human level is excessively 

 speedier and often far more stable than anything that has ever been 

 experimentally observed. We can see it, also, in the Behaviourist's 

 dogmatic assertion that the development of consciousness within any tj^e 

 of biological response never makes any difference in subsequent response. 

 Such dogmatism is only another instance of the experimental psychologist's 

 fatal proneness to run beyond his data. It is explicable in the light of a 

 study of the origins of Behaviourism, for it was by the adoption of 

 Behaviouristic methods alone that the investigation of animal response 

 below the human passed from the anecdotal and analogical stage and 

 became genuinely a part of biological science. But to push the principles 

 involved into the whole of human psychology is just as bad as to carry 

 out some departmental investigation into perceiving, or imaging, or thinking, 

 or some sensorial function, and then to use the results forthwith as a 

 master-key to all the problems of human determination. 



Some of the reasons why experimental psychology has often attracted 

 unfavourable criticism and failed to hold its students should now be clear. 

 In work on the special senses it has frequently attempted to deal with 

 problems that the physicist or the physiologist with their specialised 

 training could solve more satisfactorily. In dealing with the higher 

 mental processes it has been over-impressed with the necessity of 

 standardising objective situations and has constantly proceeded as iif the 

 simplification of a stimulus were equivalent to the isolation of a response. 

 Persistently it has shown imnecessary readiness to build upon specialised 

 investigations wide systems which pretend a finality and universality that 

 they do not possess. I believe the time has now come for pushing these 

 criticisms vigorously and for attempting to meet them in practice. It 

 could hardly have come much earlier. After all, whatever the limitations 

 of his outlook, it may fairly be claimed that the experimental psychologist 

 has done more than anybody else to keep alive the interest in special sense 

 problems. As for the work upon relatively more complex processes a new 

 and struggling science was almost bound to imitate methods already fully 

 established in other fields and to exploit them as far as they would go. 



By its shortcomings and failures, as well as through its successes, 

 experimental psychology has been attaining the rank and outlook of a 

 biological science. I will conclude this survey by saying as definitely as 

 I can what I take this to mean. 



Experimentalists everywhere are directly concerned with a study of 

 the conditions under which the observable results that interest them can be 

 shown to occur. In psychology the experimentalist is attempting to find 

 out the conditions of the various reactions or modes of conduct that 

 make up the lives of animals and human beings. At the human level 

 most of these reactions appear to be accompanied and in part determined 

 by some form of content : by sensations, images, judgments, trains of 

 reasoning. Sometimes the psychological experimenter prefers to put 

 his problems directly in terms of these, of how they occur and how, 

 when they have occurred, they may, as conditions, influence other forms 



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