GENETIC TYPE AND THE ENDOCRINES 571 



lias taken on a specific meaning, e.g., a place where food is 

 presented. It is possible that this relationship between the 

 organism and its immediate environment is one of the most 

 important in behavior. The training is considered ended 

 when the animal reaches a point where there are no further 

 changes in behavior from day to day. 



The behavioral picture of the highly active group B is 

 in direct contrast to that shown by the dogs of group A. 

 These dogs never passively fit into the situation. They seem 

 unwilling to enter into the training, but this is probably not 

 so much unwillingness as difficulty in restraining themselves 

 and a high degree of responsiveness to every change in the 

 environment. These dogs never reach a level of stereotyped 

 and predictable performance, as do those of the lethargic 

 group. It is impossible to control the environment so defi- 

 nitely that their reactions fit into a groove. Whether the 

 variation in action is due to excitation aroused by the external 

 situation, or is the result of internal stimulation, cannot be 

 determined on the basis of the present experiments. It is 

 certain, however, that these animals do not reach a phase 

 where they passively go through the performance. They re- 

 main active and alert at all times. They continue to orient 

 to the food pan and are impatient of waiting. This may indi- 

 cate that what has been termed the "attitude" or "set" as 

 determined by the laboratory instruction is constantly re- 

 leased by the break-down of inhibition. This is similar to 

 impatience in human behavior. It is this difference in "set" 

 which accounts for the reaction to the negative. From the 

 point of view of the observer, it may be said that these 

 animals always expend energy, even though overtly it seems 

 unnecessary. Such unnecessary movements as shifting the 

 position, intermittent pawing with the foot, chewing on the 

 harness, etc., are indicative of an inability to hold energy 

 in reserve. They seem unable to dam up their energy, so 

 to speak, as do the dogs of group A, but are forced to release 

 it. The dogs of group B take an active part in the perform- 

 ance, and were they allowed to follow their own inclinations 



