FREE BOOKS

Author's List




PREV.   NEXT  
|<   156   157   158   159   160   161   162   163   164   165   166   167   168   169   170   171   172   173   174   175   176   177   178   179   180  
181   182   183   184   185   186   187   188   189   190   191   >>  
ipulated objects in connection with food getting with the left hand. Figures 23 and 24 of plate V, show him reaching for a banana with the left hand. Likewise, figure 34 exhibits the use of the left hand in the draw-in experiment. So marked was Julius's preference for his left hand that I became interested in observing similar phenomena in the monkeys. Skirrl, when driving nails, held the hammer with his left hand and the nail with his right hand. The fact that he never was observed to reverse the use of the hands is surprising, for other observations indicate that he preferred the right hand for certain acts. Stimulated by the obvious left-handedness, in certain connections, of Julius and Skirrl, I tested the preference of several of the monkeys in the following simple way. Standing outside the cage I would hold out a peanut to a hungry animal, keeping it so far from the cage that the monkey could barely reach it with its fingers. I noted the hand which was used to grasp the food. Next I varied the procedure by placing the peanut on a board in order to make sure that I was not definitely directing the animal's attention. With Sobke the following results were obtained. In forty trials given on two different days, he reached for and obtained the food each time with his left hand. Only by holding the bait well toward the right side of his body was it possible to induce him to use the right hand. So far as may be judged from these observations and from others in connection with the experiments, this animal is definitely left-handed. With Skirrl the results are strikingly different. As stated above, he used the hammer consistently with his left hand, but in twenty attempts to obtain food by reaching, he used his right hand seventeen times and his left only three times. It was quite as difficult to induce him to use his left hand for this purpose as it was to induce Sobke to use his right. We must therefore conclude that Skirrl is right-handed in connection with certain movements and left-handed in others. The monkey named Gertie in the reaching experiment consistently used her left hand, never once using the right. Jimmie, so far as it was possible to make tests with him, also used his left hand, but it should be said that the results are unsatisfactory because he was at the time extremely pugnacious and paid attention to the experimenter rather than to the food. Scotty, in the first series of ten trials, used
PREV.   NEXT  
|<   156   157   158   159   160   161   162   163   164   165   166   167   168   169   170   171   172   173   174   175   176   177   178   179   180  
181   182   183   184   185   186   187   188   189   190   191   >>  



Top keywords:

Skirrl

 

animal

 
results
 

connection

 

handed

 
reaching
 

induce

 
hammer
 
peanut
 

consistently


observations
 

monkey

 

experiment

 

attention

 

trials

 

obtained

 

Julius

 

monkeys

 

preference

 
experiments

reached
 

holding

 

judged

 
difficult
 
unsatisfactory
 

Jimmie

 

extremely

 
Scotty
 

series

 

pugnacious


experimenter
 

Gertie

 

obtain

 
seventeen
 

attempts

 

twenty

 

stated

 

conclude

 

movements

 
purpose

strikingly

 
driving
 

phenomena

 
observing
 
similar
 

preferred

 
surprising
 

observed

 

reverse

 
interested