THE INTELLIGENCE OF MAMMALS 243 



good memory for any combination they may have learned. 

 Three raccoons which had learned to open the box with 

 seven fastenings were put into the box again after an interval 

 of 147 days. Only one individual succeeded in undoing all 

 of the seven fastenings and escaping. His tunes hi four 

 successive trials were 34, 28, 131, and 182 seconds. The 

 other two worked most of the fastenings, but generally 

 failed to undo a horizontal lock. Davis found that rac- 

 coons remembered how to undo the fastenings of a puzzle 

 box for over a year. 



One significant feature of the raccoons' method of attack 

 on their problems is that they employ different means of 

 accomplishing the same result. They worked fastenings 

 with either the right or the left paw or with both together. 

 "All of the raccoons turned a button once or twice with 

 the nose in early trials, then settled down to working it with 

 the paw." This looks very much as if there were something 

 besides the sensori-motor associations assumed by Thorn- 

 dike. We cannot say that there is nothing but the asso- 

 ciation of the sight of a certain object with a particular 

 impulse to movement, it in effecting a certain change an 

 entirely different organ is substituted for the one pre- 

 viously employed. When an animal moves with its paw a 

 fastening it formerly moved with its nose it gives evidence 

 of being guided by an idea of what it is setting out to 

 accomplish. 



Evidence for the existence of ideas was derived also from 

 other sources. It was found that raccoons were able to 

 associate being in a box with getting food after they came 

 out, so that when they were dropped in, as in the experi- 

 ment with the cats, they came after a while to go into the 

 box of their own accord. The motor impulse to enter the 

 box was not in these cases an element hi the association 



