GENETIC TYPE AND THE EXDOCRIXES 535 



ANALYSIS OF BEHAVIOR IN THE CONDITIONED FOOD 

 TAKING SITUATION 



These experiments were conducted to determine the range 

 of behavior among the dogs in a food taking situation. From 

 an observation of the animals under kennel conditions, wide 

 differences in behavior were readily noted, and members of 

 the first group selected for study were pure bred animals 

 showing most obvious contrasts. Hybrid offspring of these 

 dogs were also trained; and then others were chosen for a 

 variety of reasons. 



From the point of view of the observer, the conditioned 

 food taking performance may be divided into definite patterns 

 of action. The dog must first become acquainted with the 

 experimenter and learn to lead on a leash. Next, it must be- 

 come accustomed to the laboratory, the cup for recording 

 saliva, the pneumograph, and the apparatus used to record 

 postural movements. When the dog has become sufficiently 

 familiar with the laboratory to take food, the conditioning 

 signal is applied. 



In the beginning, the signal is given simultaneously with 

 the presentation of food. The performance at this time may 

 be considered a series of excitatory and inhibitory phases 

 and is represented graphically as follows: 



Food Pood 



Cond. St. Rotation of disk Cond. St. Rotation of disk Cond. St. 



j Inactivity | Inactivity |~~ 



This procedure is repeated a number of times. When the 

 food is then withheld for a few seconds after the signal is 

 presented, the conditioned salivary reaction appears. In con- 

 trast to the above diagram this performance is represented 



as follows: 



Food Food 



Cond. St. Rotation of disk Cond. St Rotation of disk 



Inactivity 



Cond. Salivary 

 response 



Inactivity 



