Allen, Association in the Guinea Pig. 317 



The experiments were repeated on four different groups of 

 young during an interval of five months. The smaller ones 

 were always a little later in their solution of the problems than 

 their larger brothers, because their movements were neither so 

 rapid nor so numerous. When the way was once found they 

 remembered as accurately as the others. 



C. Summary of Work With Young. 



1. The guinea pig at birth is physically mature with the ex- 

 ception of slight muscular weakness and inaccurate coordi - 

 nation. 



2. That no experimental indications of associative processes 

 were obtained at the age of one day seems to be due to the 

 small amount of activity at that time. 



3. All individuals examined learned a simple path to their 

 mother at the age of two days. 



4. The most complex problem solved at all was solved at 

 the age of three days, and the recognition of it persisted. 

 There was no indication of increase in complexity of psychical 

 processes after the third day. The problems learned between 

 one and three days depended upon increasing activity, and not 

 upon increasing intelligence. 



5. For the reasons previously given, it is probable that 

 kinesthetic sensations are of paramount importance in deter- 

 mining the recollection of a path. 



///. Experiments With the Adult. 



It was found that if the guinea pig had been without food 

 for twenty-four hours, the odor and sight of food were sufficient 

 to induce continuous movement for a considerable length of 

 time, and if mere activity could solve the problem it was most 

 quickly solved under these conditious. 



Objections have been made by Mills ^ and by Morgan ' 

 that experiments upon animals which have been starved before- 

 hand were rendered invalid by the abnormal conditions. In 

 my experimental work on the guinea pig I have not been igno- 



' Psychological Review, Vol. VI, p. 265. 

 - Animal Behavior, p. 151. 



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