Effect of early environmental restriction on subsequent behavior in the rat

The Psychological Record - Three groups of rats were raised in (a) unrestricted, (b) community cage, and (c) isolated environments respectively. The community and isolated cages were barren while...     

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.     

Effect of the difficulty of prior items on the magnitude of judgments of learning for subsequent items

Research on metacognition often uses various kinds of paired-associate items (e.g., foreign language translation equivalents) to investigate judgments of learning (JOLs) under the assumption that the JOLs are made independently of each other. We tested this assumption by exploring the effect of manipulating the difficulty of prior Swahili-English translation equivalents to determine whether there is a contrasting change in the magnitude of the JOLs assigned to subsequent Swahili-English translation equivalents (e.g., intermediate-difficulty items might receive lower JOLs when following easy items than when following difficult items). The magnitude of JOLs for the subsequent items did not vary as a function of the difficulty of the prior items, even when there were 10 prior items of homogeneous difficulty that differed from the difficulty of the subsequent to-be-judged items.