52 Animal Intelligence 



The advantage due to experience in our experiments is 

 not, however, the same as ordinarily in the case of trained 

 animals. With them the associations are with the acts or 

 voice of man or with sense-impressions to which they natu- 

 rally do not attend (e.g. figures on a blackboard, ringing of 

 a bell, some act of another animal). Here the advantage 

 of experience is mainly due to the fact that by such ex- 

 perience the animals gain the habit of attending to the 

 master's face and voice and acts and to sense-impressions 

 in general. 



I made no attempt to find the differences in ability to 

 acquire associations due to age or sex or fatigue or circum- 

 stances of any sort. By simply finding the average slope 

 in the different cases to be compared, one can easily demon- 

 strate any such differences that exist. So far as this dis- 

 covery is profitable, investigation along this line ought now 

 to go on without delay, the method being made clear. 

 Of differences due to differences in the species, genus, etc., 

 of the animals I will speak after reviewing the time-curves 

 of dogs and chicks. 



In the present state of animal psychology there is another 

 value to these results which was especially aimed at by the in- 

 vestigator from the start. They furnish a quantitative esti- 

 mate of what the average cat can do, so that if any one has an 

 animal which he thinks has shown superior intelligence or 

 perhaps reasoning power, he may test his observations and 

 opinion by taking the time-curves of the animal in such 

 boxes as I have described. 



If his animal in a number of cases forms the associations 

 very much more quickly, or deals with the situation in a 

 more intelligent fashion than my cats did, then he may have 

 ground for claiming in his individual a variation toward 

 greater intelligence and, possibly, intelligence of a different 



