26 Animal Intelligence 



doning the old method one ought to seek above all to 

 replace it by one which will not only tell more accurately 

 what they do, and give the much-needed information how 

 they do it, but also inform us what they feel while they act. 



To remedy these defects, experiment must be substituted 

 for observation and the collection of anecdotes. Thus you 

 immediately get rid of several of them. You can repeat the 

 conditions at will, so as to see whether or not the animal's 

 behavior is due to mere coincidence. A number of animals 

 can be subjected to the same test, so as to attain typical 

 results. The animal may be put in situations where its 

 conduct is especially instructive. After considerable pre- 

 liminary observation of animals' behavior under various 

 conditions, I chose for my general method one which, simple 

 as it is, possesses several other marked advantages besides 

 those which accompany experiment of any sort. It was 

 merely to put animals when hungry in inclosures from which 

 they could escape by some simple act, such as pulling at a 

 loop of cord, pressing a lever, or stepping on a platform. (A 

 detailed description of these boxes and pens will be given 

 later.) The animal was put in the inclosure, food was left 

 outside in sight, and his actions observed. Besides record- 

 ing his general behavior, special notice was taken of how he 

 succeeded in doing the necessary act (in case he did succeed), 

 and a record was kept of the time that he was in the box 

 before performing the successful pull, or clawing, or bite. 

 This was repeated until the animal had formed a perfect 

 association between the sense-impression of the interior of 

 that box and the impulse leading to the successful movement. 

 When the association was thus perfect, the time taken to 

 escape was, of course, practically constant and very short. 



If, on the other hand, after a certain time the animal did 

 not succeed, he was taken out, but not fed. If, after a suffi- 



