日本財団 図書館


Sheet 67

 

REWARD OR REPRIMAND, WHICH IS MORE EFFECTIVE ?

Experiment on the Learning Process of Flies

 

An experiment on the learning process of flies was conducted as follows.

Of three tubes, tube A was left untouched, tube B was dipped in octanol(OCT) and tube C dipped in methylcyclohexanol (MCH) mixed with sugar water which attracts flies. A group of flies were placed in tubes A, B and C consecutively for one minute apiece. This process was repeated several times (the Training Stage).

 

166-1.gif

 

After this training stage, the flies were then put into the choice chamber described below; tube A was left untouched, tube B was dipped in OCT and tube C dipped in straight MCH with no sugar water mix. Lighting sources were installed at the back of each tube to attract flies, which, by their nature, are attracted to any form of illumination. The flies were expected to move into the tubes in response to this light source (the Testing Stage).

When placed midway between tube B and tube C, however, more flies moved into tube C. Since flies do not under normal circumstances acknowledge any difference between OCT and MCH, the results indicate that the flies have presumably been conditioned to make a positive association between MCH and sugar water at the training stage.

Following this, a similar test was conducted. This time, in the training stage, tube C was dipped in MCH as before but in replacement of the sugar water mix, an electric current was installed to provide an electric shock. At the testing stage, when flies were placed midway between tube B and C, most flies moved into tube B even though the electric current had been removed from tube C. This result suggests that the flies have been conditioned to make a negative association between MCH and electric shock at the training stage.

The learning effects of the above two tests differed in terms of learning speed and memory duration. The time required to condition flies to a positive association (duration of the training stage) was 100 minutes while the time for a negative association was 30 minutes.

Regarding the effects of training, the memory of positive association lasted for 24 hours (the duration of time in which the flies continued to choose tube C without sugar water). The duration for the memory of negative association was 4-6 hours.

The results of these tests indicate that pain makes flies learn certain behavior more quickly than when offered a reward. They also denote that behavior learned by positive conditioning has a larger lasting effect than that learned by negative conditioning.

 

 

 

BACK   CONTENTS   NEXT

 






日本財団図書館は、日本財団が運営しています。

  • 日本財団 THE NIPPON FOUNDATION