PERSEVERANCE REACTIONS IX PRIMATES AND RODENTS 11 



The marked individual differences presented by the five infra- 

 human primate subjects reflect a poHcy of selecting subjects in 

 whom oddities of general reactive equipment had been observed. 

 Monkey 26, for example, could be successfully bullied by even 

 the smallest and youngest of my monkeys in spite of the fact 

 that he was the largest but one of a band of sixteen monkeys 

 and baboons that lived together for several months in a single 

 band. Monkey 16, whose record is in striking contrast to that 

 of Monkey 26, is the least distractible monkey that I have ever 

 owned. Monkey 5, on the other hand, is not only distractible 

 to a high degree, but unusually stupid in her social relations. 



The gophers, roof rats, black rats and mouse were all wild 

 subjects. None was used until it had been at least two weeks 

 in captivity. The white rats belong to two different strains. 

 White Rats 5, 6 and 8 were born in the laboratory, their parents 

 being White Rats v-? and 4 of the list. 



PRESENTATION OF RESULTS 



I 



Six general types of searching response were manifested by 

 the various subjects: 



1. Response with reference to the experimenter s rule that no 

 alley is the right alley for two successive trials. 



It is obvious that if a subject respond consistently with refer- 

 ence to this rule (but without inferred or other knowledge of 

 the experimenter's order) he will have an average chance of 

 being required to try but one of the three inferentially possible 

 alleys during each of one-third of his trials. If he learns the 

 always-one-impossible-alley rule during his preliminary trials, 

 and never departs from it during his 100 formal trials he will 

 have an average chance of effecting his escape from the appa- 

 ratus 100 times by trying the various alleys 200 times. 



In constructing tables of results I have employed the desig- 

 nation, " Type A" to indicate reactions of the kind just de- 

 scribed. The cases in which the subject tries only one or two 

 of the three inferentially possible alleys cannot properly be 

 classified as Type A reactions, since one cannot be sure that an 

 inferentially possible alley would have been chosen had a third 



