HABIT FORMATION IX THE DOG ^ 45 



only b}^ the high overtones, which in tones as nearly pure as 

 those sounded on this apparatus, may have been lacking or so 

 faint as not to be effective. There is of course, no proof of this 

 but the point may be found worthy of future tests. These are 

 not practicable at the present time. 



It has been suggested by a critic that the stimulus chosen — 

 a pure tone — is one so different from those stimuli to which the 

 animal is pro^•ided with some form of instinctive response, that 

 the animal should not be expected to learn readily to respond 

 to it. Inasmuch as a pure tone cannot be localized, there may 

 be some force to this suggestion. It seems to the cafsual observer 

 at least that most of the auditory stimuli which affect the dog 

 are significant because they are noises which can be localized 

 and quickly associated with the things making them. However, 

 admitting this point, the fact remains that it is useless to try to 

 test any theory of localization of the center for pitch by experi- 

 menting on the dog, unless the animal can be made to discrim- 

 inate on the basis of pitch-difference alone. This fact can be 

 established only by the use of pure tones as stimuli, and by 

 working under some such conditions as are proposed above as 

 a standard. It is also open to question whether discrimination 

 could not yet be established if by proper means the animal 

 could be made to receive the stimuli. 



The suggestion was also made that in the stimulus -cage the 

 animal is in a "highly artificial" situation, and reacts under 

 emotional constraint. This point is made much of by Shepherd, 

 also, in his discussion of experiments in vision ^'. 



The truth of the first half of this suggestion is of course patent. 

 Any experiment made under conditions of sensory control is 

 necessarily "artificial." The animal which turns at the flutter 

 of a bird in the leaves is probably affected by visual, olfactory 

 and possibly still other stimuli than auditory. These stimuli 

 taken together with the sound form the "situation" in which 

 the animal is, and are readily associated with the response, 

 which is more or less instinctive. The additional auditory stim- 

 ulus may be only a "contributing agent," which makes the 

 action of the others eft'ective. The animal may be compared to 

 the subject in a reaction-time experiment, prepared to react 



^* Shepherd, W. T. Mental processes of the Rhesus monkey. Psychological 

 Monographs, 1911. 



