The effects of distributed training on retention of operant conditioning in human infants

Long-term retention of operant footkicking acquired in the mobile conjugate reinforcement paradigm was assessed as a function of the distribution of training time. In the first study, 3-month-old infants were trained for either one 18-min session or for two 9-min or three 6-min sessions separated by 24-hr intervals. All infants exhibited retention during a test administered immediately after training, but only those trained in a single session continued to perform the conditioned response during cued-recall tests 7 or 14 days later. Infants trained in three sessions showed no evidence of remembering the contingency even after a week. A warm-up decrement, seen in the day-to-day performance of infants in the distributed conditions, was eliminated in the second study by the interpolation of a nonreinforcement period at the outset of daily sessions. This procedure also enhanced long-term retention such that infants trained in three 6-min session now remembered the contingency for 14 days and did not differ from infants who had received a single 18-min session. Whether distributed training facilitates or impairs long-term retention appears to depend on the opportunity for infants to acquire a sufficient number (or kind) of effective retrieval cues during original learning.     

Discrimination and generalization by rats of temporal stimuli lasting for minutes

In three experiments, rats learned to respond differentially to reinforced and nonreinforced trials when the length of the intertrial interval (ITI) predicted the trial outcome (reinforcement or nonreinforcement). Rats in control groups, for whom the length of the ITI did not predict the outcome, did not show differential performance on nonreinforced and reinforced trials. Generalization gradients obtained following discrimination training were comparable to those obtained following discrimination training with other types of discriminative stimuli. That is, groups which had shown differential performance in discrimination training yielded generalization gradients with fastest speeds at the previously reinforced ITIs, slowest speeds at the previously nonreinforced ITIs, and intermediate speeds at ITIs of intermediate length. Control groups yielded flat gradients across all ITIs tested. These effects were shown for relative time discrimination (short time = reinforcement, long time = nonreinforcement, or the reverse) and also for an absolute time discrimination (long and short time = reinforcement, middle time = nonreinforcement or the reverse). This method was effective for time duration measured in minutes rather than seconds, as is more commonly the case.     

Dynamic processes in music perception

A schema-based theory of music perception that describes the dynamic interaction between the musical event and the listener’s knowledge of the underlying regularities in tonal music is proposed. Three properties of musical schema are evaluated in a recognition memory experiment: (1) The schema engages a subset of the abstract knowledge system that is determined by the predominant key of the musical sequence, (2) the schema evaluates both interval relations and the functions of the sounded elements within the established tonal framework, and (3) the schema interacts continuously with the musical event in time to process pitch information in its temporal context. Listeners are required to identify the serial position of a chord that is changed between two successive chord sequences that are otherwise identical. The experiment measures the magnitude and the temporal extent of the disruptive effect of including in the sequence an element outside the tonal framework. The results show temporally specific effects on memory for pitch relations consistent with the operation of a musical schema. Comparisons are made with schema-based theories applied in other perceptual and cognitive domains.     

Working through a group's fantasy of the deceased leader's wish for the group's continuation

This paper reflects the working through of a group's fantasy that the deceased group leader wished the group to continue. As in any defense, the fantasy protected members from the pain of the finality of the leader's death. This article reveals the subjective experience concerning the effect of the leader's death on the group and members' intrapsychic struggle to separate and individuate from the deceased leader, while attending to and striving toward the group's continuation. The group's painful and growing individuation enabled the group to follow its own tasks without the spector of the deceased leader.     

The Effects of Procedures, Social Accounts, and Benefits Level on Victims' Layoff Reactions

Three hundred and fifty-three layoff victims responded to questions describing their reactions to layoffs. Victims also described management layoff practices. Two measures of procedural fairness in layoff practices (decision-making characteristics and social accounts) and one measure of layoff outcomes (benefits level) were included. Only decision-making characteristics predicted exemployee willingness to recruit for a former employer and desire for regulation of layoffs. These results provide further evidence of the importance of procedural justice in organizational decision-making.     

Somatic complaints in anxious children

Although stomachaches and headaches are considered characteristic of children with anxiety disorders, there is converging evidence that a broader range of somatic symptoms may be associated with children's expressions of anxiety. The purpose of this study was to determine the prevalence of somatic complaints in anxious children. The results indicated that children with anxiety disorders endorsed the presence of many different somatic complaints, and that contrary to clinical intuition, stomaches and headaches were not among the most commonly reported symptoms. In addition, the anxious children endorsed significantly more somatic complaints when compared to normal controls. Furthermore, the symptom pattern reported by anxious children indicated the presence of both the somatic and cognitive components usually associated with panic attacks, although none of the children met diagnostic criteria for panic disorder. The results are discussed in terms of the contribution of somatic symptoms to the understanding of anxiety disorders in children.     

Depression and processing information about others

We investigated differences between mildly depressed subjects and normal controls in their memory for, and judgments of, another person. All subjects read a story (containing either predominately positive or predominately negative items) under instructions to form an impression of the story target. Subjects later made several judgments about the target and attempted to recall the story. For both the positive and the negative story, depressed subjects produced significantly more negative intrusions (i.e., recalled nonpresented negative items) than did the normal subjects, but they did not recall more negative items correctly than did the normal subjects. Depressed subjects also perceived themselves as more similar to the negative story target than did the normal controls and indicated greater liking for the negative story target than did the normal controls.