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W HODOS

Publications and source records attributed to W HODOS.

11 recordsLinked to original sources
PubMed1963

Effects of increment size and reinforcer volume on progressive ratio performance.

The progressive ratio schedule requires the subject to emit an increasing number of responses for each successive reinforcement. Eventually, the response requirement becomes so large that the subject fails to respond for a period of 15 min and thereby terminates the session. This point is arbitrarily defined as the "breaking point" of the subject's performance. The measure is quantified in terms of the number of responses in the final completed (i.e., reinforced) ratio run of the session. Previous work has shown that this measure varies as a function of several motivational variables and may thus be useful as an index of reinforcement strength. The present study is an extension of that work. The subjects were four rats. In the first experiment, the effects of the size of the increment by which each ratio run increased were studied. In two additional experiments, the volume of a liquid reinforcer was varied using both large and small ratio increments. The results indicate that the number of responses in the final completed ratio run increases as a function of the size of the ratio increment. However, the number of reinforcements obtained by the animals per session declines sharply. When large ratio increments are used, the number of responses in the final ratio increases as a function of the volume of the reinforcer, but when small increments are used, progressive satiation results in a decline in performance with the larger volumes of liquid.

Animals↗
PubMed1962

Electroencephalographic correlates of temporally spaced responding and avoidance behavior.

This study was undertaken to determine whether any EEG changes occurred during a multiple schedule of reinforcement consisting of repeated periods of avoidance behavior, a time-out (TO) period, and a period of differential reinforcement of low rates (DRL). The two monkeys were permanently implanted with bipolar electrodes in various subcortical areas. The EEG was recorded from these electrodes for several weeks before any behavioral training was undertaken. Training was then begun in the multiple schedule, and EEG recordings were taken frequently throughout the training period. When a stable performance level was achieved, drugs (dl-amphetamine and sodium pentobarbital) were introduced which disrupted the DRL performance but had little or no effect on avoidance behavior. The EEG recordings continued throughout these drug studies. The data indicate that the marked behavioral differences noted in each component of the schedule were not reflected in the EEG. However, the EEG did correlate with the general level of alertness of the animals during the various components. The drugs which differentially affected the behavior in the components of the schedule did not differentially affect the EEG, but they did change the brain-wave activity equally in all components. Finally, EEG changes correlated with the complex motor response of lever pressing were not observed.

Animals↗
PubMed1962

Complex response patterns during temporally spaced responding.

A series of experiments is reported in which two monkeys emitted complex response patterns, not specified by the experimental program, during the DRL component of a multiple schedule. Administration of sodium pentobarbital and dl-amphetamine, drugs which disrupted the DRL performance, were also observed to suppress these collateral responses. Sequences of these collateral responses appear to mediate, at least in part, the timing process required for reinforced performance on the DRL schedule.

Amphetamine↗
PubMed1961

Progressive ratio as a measure of reward strength.

Four rats were trained to press a lever on a ratio schedule of reinforcement in which the number of lever presses required on each consecutive run increased by a fixed increment. Both concentration and volume of the reward were varied. Relationships were obtained between reward and deprivation variables and the size of the final completed ratio run.

Animals↗
PubMed1961

Behavioral method for study of pain in the monkey.

A behavioral method is described in which increasing intensities of electric shocks were applied to the gasserian ganglia of alert monkeys. The animals were trained to press a lever to regulate the shock level. "Pain thresholds" were thereby obtained, and these thresholds were modified by varying the shock duration and by administration of morphine.

Animals↗