Abstract
A compound stimulus consisting of tone and light was conditioned to an electric-shock US in two groups of rats. For the experimental group, the light stimulus had been paired with food prior to the compound conditioning. No such treatment was given to the control group. After the compound conditioning, the light and the tone were presented separately during Test Phase. An appetitively-motivated behavior (‘magazine’ behavior) and an aversively-motivated behavior (‘freezing’ behavior) during CS presentations were analyzed based on the videotape-recorded data. The main findings of the experimental group during Test Phase were as follows; (1) The light stimulus which had been conditioned to food was conditioned very little to the electric shock. (2) Rats showed ‘magazine’ behaviors during the light presentations even in Test Phase. (3) The ‘freezing’ behaviors were observed at a lower level than in the control rats during the presentation of the tone. These results were discussed in terms of reciprocal interactions of appetitive and aversive motivational systems.
