EFFECT OF LENGTH OF BLIND ALLEYS ON ^L\ZE LEARNING 43 



explain behavior, unless in such cases we understand how the 

 ideal dispositions themselves are acquired. The use of the 

 term idea in the higher forms of behavior is justified then only 

 on the basis of simplicity of statement. There is none but 

 questionable evidence thus far that ideational behavior is different 

 in any way but degree from sensori-motor, or the well known 

 trial and error, behavior. " Ideas " can function only when 

 the somewhat detachable dispositions, of which they are the 

 imperfect, subjective aspects, have been built up by experience, 

 and such dispositions require a rather complex nervous mechan- 

 ism. It is needless to say that no evidence of ideational behavior 

 has been found in the white rat. While, as has been pointed 

 out in the foregoing, there are likely some hold-over effects of 

 stimuli in the case of the rat, these likely operate more or less 

 mechanically and en masse so that the animal enjoys little 

 independence of action and is subject rather completely to the 

 dominance of the group of stimuli present or immediately past. 

 That is to say, the animal can respond only to present situations 

 though with a considerable number of random variations, until 

 the most consistent responses to that situation have fixed them- 

 seUes to the exclusion of all others, after many repetitions of 

 tiials. Then the response becomes uniform and mechanical to 

 a high degree. 



The more advanced behavior as we see it in the case of 

 man — ideational behavior — differs from the lower forms illus- 

 trated in the present study in that it is less fixed and less 

 dependent upon immediate situations. Stimulus-response organ- 

 izations, or tendencies, are more detachable in their separate 

 smaller functional components; and the latter have richer pos- 

 sibilities of combinations among themselves, on the one hand, 

 and on the other there is less dependence for their functioning 

 upon direct or immediate stimulation. Various indirect and 

 vicarious stimuli come to serv^e adequately. Thus various 

 systems of stimulus-response mechanisms may become organized 

 into inconceivably complex relationships about certain symbolic 

 stimuli, such as written or spoken words, various kinds of gestures 

 and attitudes of the stimulating individuals, associated objects, 

 sounds, contacts, and so on. It then becomes practically impos- 

 sible to predict which of the various aspects of the situation 

 will succeed in calling out its particular response. We shall 



