| Popis: |
Rats were trained to press a lever for food according to a variable-interval (VI) 60-sec schedule of reinforcement. They were then divided into four groups and received 10 sessions of either extinction or response-independent pellets delivered according to a variable-time (VT) 30-, 60-, or 120-sec schedule. Leverpressing was reduced at approximately the same rate for subjects receiving extinction, VT 30- and VT 120-sec pellet deliveries. Relative to thse groups, the VT 60-sec group exhibited slower reductions in responding. Subjects in the three VT groups were most frequently observed to contact the food magazine, whereas, subjects in the extinction group typically faced away from the magazine and appeared to be sleeping. |
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