PSYCHOLOGY — FRANZ. 239 



PSYCHOLOGY. 



Franz, S. I., Government Hospital for the Insane, Washington, District of 

 Columbia. Grant No. 80. Investigation of the functions of the cere- 

 brum. (For previous reports see Year Books Nos, 4-9.) $1,000 



During the year (September i, 1910, to August 31, 191 1) work on the; 

 cerebrum has continued. Much of that which was reported "in progress" in 

 1910 has been finished, and has either been published or is ready for publi- 

 cation, 



(i) An account of a research into the mental processes of the monkey, 

 which was performed by Dr. W. T. Shepherd under my direction, has been 

 issued as a monograph supplement to the Psychological Review. This work 

 was performed with monkeys which were later utilized by me in tests of the 

 relation of the cerebrum to mental processes, and it is of special interest 

 because methods have been employed which are also utilized for the investi- 

 gation of the relation of the mental processes to different parts of the cere- 

 brum. The conclusions formulated from this work are as follows : Monkeys 

 learn to discriminate brightness, but take a long time for this when the 

 stimuli have not a direct relation to the incentive for work ; only a few trials 

 are needed when the visual qualities are a part of the objects to which they 

 naturally pay attention. Colors are discriminated with accuracy and rapidity 

 when they are parts of the food (red, pink, yellow, and green). Three ani- 

 mals gave clear indications of the discrimination of different degrees of 

 noises, and also learned to discriminate musical tones. The habits are formed 

 rapidly if there be the double incentive of pleasant food as an inducement to 

 a correct response and of an unpleasant stimulus to check a wrong response. 

 From the experiments it appears that monkeys learn to inhibit recently 

 formed habits of action with facility. As far as the evidence goes, in regard 

 to both the formation and the inhibition of habits, monkeys are far superior 

 to raccoons, dogs, cats, elephants, otters, and other mammals which have 

 been investigated. Monkeys have a practical memory; they appear to show 

 a good degree of retention, but the representative function in memory is an 

 unknown quantity. Of the higher powers of mind, the monkey has only 

 rudiments. He has a something which corresponds in function to ideas of 

 a low order and which serves practical purposes. This something we call, 

 with Hobhouse, practical ideas. Two of the monkeys learned by imitation, 

 but six others gave no indication of imitation ability. It may be said that 

 while monkeys may learn by imitation to a limited extent, imitation as in- 

 volving ideation is a small factor in their ordinary learning process. All the 

 tested animals appeared to reach a generalized mode of action in dealing 

 with problems, but there seemed to be no evidence of true general notions. 

 They have an adaptive intelligence, a lower form of reason, or a mental state 

 inferior to true reason. 



(2) During the year an article "On the association functions of the cere- 

 brum" has been published. In this article there is given an hypothesis re- 



