Effect of prior Pavlovian discrimination training upon learning an operant discrimination

The effect of Pavlovian discrimination training with two stimuli upon subsequent learning of an operant discrimination involving those stimuli was studied. After preliminary lever press training, the lever was removed and thirsty rats received noncontingent pairings between S₁ (a tone or a clicker) and water reinforcements, whereas S₂ (a clicker or a tone) occurred always without reinforcement. This procedure presumably established S₁ as a positive CS for respondent behavior, whereas S₂ was established as an inhibitory CS. Following this training, the lever was reintroduced and the rats were trained on an operant (lever pressing) discrimination involving S₁ and S₂. For the Consistent Ss, S₁ was the S^D and S₂ the S^Δ in the operant discrimination; for the Reversed Ss, S₂ served as S^D and S₁ as S^Δ. The Consistent Ss learned the operant discrimination significantly faster than did the Reversed Ss. The result emphasizes the importance of respondents, conditioned to S^D and S^Δ, which modulate operant performance to these stimuli.     

Verbal versus manual reaction time in schizophrenic and normal subjects

On the assumption that schizophrenia involves a disturbance in interpersonal relations it is predicted that the verbal reaction time responses of schizophrenic subjects should have disproportionately longer latencies than manual reaction time responses as compared to normal subjects. Using data presented in this Journal by Venables and O'Connor (1959). the prediction is confirmed for patients whose reaction time level is relatively fast, but not in those with relatively slow reaction times. Several possible mechanisms are postulated to account for the results, including differential reinforcement, amount of practice, and complexity of verbal responses, and degree of pathology of the patients.     

Deferred decision in human signal detection: A preliminary experiment

In the detection task characterized by deferred decision, the observer is allowed to determine how many observations he will make before deciding whether or not a signal is present, and he is called upon to balance the goals of maximizing accuracy and conserving time. The human observer appears capable of using the optimal process of cumulating sensory information over successive observations, but certain common training procedures lead him to use a less efficient process. Though he displays a consistent decision bias, his performance is also in good agreement with the optimal model of the process of terminating a sequence of observations.