Patterns of Human Behavior 1 79 



tion becomes more difficult, the psychologist makes a pencil mark 

 on the back of the ellipse in order to distinguish it from the "circle." 

 He also uses a coin or some other randomizing device to decide 

 which of the stimulus objects he is going to administer next. He 

 cannot afford to administer them in any patterned order which 

 the dog might learn. Finally, these two objects become indis- 

 tinguishable; i.e., from the point of view of the dog they are one 

 object or, rather, they would be one object if the dog had not 

 been told previously, "This is a context for discrimination." This 

 message was underlined during the period when discrimination was 

 difficult but still possible. 



The message, "This is a context for discrimination," is carried 

 partly by the earlier training and partly by every circumstance 

 of the laboratory, the harness, the smell of the experimenter, and 

 so forth. All these ancillary stimuli are, in fact, indications to the 

 dog that he is now in a context for discrimination. At this point, 

 the dog starts to show grossly disturbed behavior; it may bite its 

 keeper, refuse food, become comatose, etc. 



If the experiment is started with a naive dog and the preliminary 

 training in discrimination is omitted, the dog does not go crazy. 

 If you start with a dog untrained in discrimination and present 

 a single stimulus object (flipping a coin to decide what this object 

 shall mean), the dog has to guess and will do the appropriate 

 thing; it will gamble on the difference. The dog cannot toss a 

 coin, but it settles, in general, to approximately the probabilities 

 which it experiences. If the stimulus object means \ 70 per cent of the 

 times and )' 30 per cent of the times, the dog will settle to guessing 

 at .V 70 per cent of the time and guessing at y 30 per cent of the time. 

 This is not the ideal course which the sophisticated gambler would 

 follow; he, of course, would bet on x 100 per cent of the times be- 

 cause it gives more frequently the positive reinforcement. 



What happens, it seems to me, in the pathogenic experiment is 

 that the experimenter succeeds in communicating to the dog a 

 message about the contingency patterns in which it is to find 

 itself, and this message happens to be an untrue message. The 

 dog is in a probabilistic situation, but the experimenter has con- 

 vinced the dog that it is in a discrimination situation, at which 

 point very severe pathological changes start to appear. 



