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D P HENDRY

Publications and source records attributed to D P HENDRY.

7 recordsLinked to original sources
PubMed1964

PERFORMANCE ON A FIXED-RATIO SCHEDULE WITH CORRELATED AMOUNT OF REWARD.

Four rats were trained to bar press on FR 9 TO 30 sec. They were reinforced with a large or small amount of water according to whether their final IRT was long or short respectively. Four control rats always received the small amount of reinforcement. The control animals produced the high rates of responding typical of fixed-ratio performance. The experimental animals, with one exception, developed superstitious behavior and maintained slow responding throughout the ratio. However, some features of the results pointed to a persistent influence of the factors which favor short IRTs.

Animals↗
PubMed1964

FIXED-RATIO PUNISHMENT WITH CONTINUOUS REINFORCEMENT.

Rats were reinforced with water for every bar-press and concurrently punished for every 10th or 20th bar-press. Punishment produced an initial suppression of responding followed by recovery. A slight change in the method of delivering punishment eventually led to a high response rate just after punishment, a low response rate just before punishment, and frequent intermediate pauses. The results are interpreted as showing that punishment became a safe signal and that the high rate of responding it released came to act as a conditioned aversive stimulus. The effects of amphetamine were consistent with this interpretation. Alcohol had the paradoxical effect of increasing pauses and depressing the low rate before punishment.

Amphetamine↗
PubMed1963

PARTIAL NEGATIVE REINFORCEMENT: FIXED-RATIO ESCAPE.

Rats were unable to sustain performance when eight bar-presses turned off shock (-FR 8). In a second experiment, thirsty rats were able to maintain a moderate response rate when performance on -FR 8 was also reinforced with water. Some rats continued to bar-press on -FR 8 after withdrawal of positive reinforcement, but at a much lower rate. A possible explanation of the results is that during intermittent escape conditioning in a free-responding situation the absence of shock itself acquires aversive properties.

Electricity↗