GENETIC TYPE AXD THE EXDOCTJXES 585 



leg was raised .46 seconds after the signal began, even though 

 the shock was never applied before the fifth second. The 

 dog responded repeatedly at about this time and was careful 

 not to lower the leg so long as the signal continued. Another 

 dog of group B responded .76 seconds after the signal began. 

 After the experiments had progressed, the dogs of group A, 

 as a rule, responded only to the shock after the 5 second 

 interval; there was no conditioned withdrawal of the leg, 

 and thus no conditioned reaction time. All other animals 

 distributed themselves between these two extremes. For 

 example, one bassethound-shepherd Fj responded after a 

 1.98 second interval, another after a 2.34 second interval. 

 One bassethound-shepherd F 2 had a delay of 1.05 seconds, 

 another of only .82 seconds. 



Tn the salivary experiments, if the duration of the condi- 

 tioning stimulus was constant, the delay of the response 

 tended to increase as the experiments continued. This was 

 not true, however, in the motor experiments, even though the 

 shock was always delayed for 5 seconds. The animals which 

 formed the avoiding reaction always responded at about 

 the same time after the presentation of the signal, although 

 there were, of course, slight variations from day to day. 



Behavior during the interval between conditioning signals. 

 The behavior during the intervals between presentation of 

 the conditioning signals is as significant in typing the dogs 

 as the reaction to the signal. During this interval the animal 

 should return to a normal level of activity. In the dogs of 

 group A there was a quick return to normalcy after the 

 shock. If the harness was used, they rested on it, or leaned 

 their heads on the food table. If the harness was not used, 

 many would lie clown or lounge with the hind quarters flat 

 on the platform. It was evident that they were in a condition 

 of half sleep, or as Pavlov termed it, a state of almost com- 

 plete inhibition. These animals did not struggle, whine, or 

 move about during the intervals, as demonstrated by text- 

 figure 101 (fig. 2).' 



