Delaying execution of intentions: overcoming the costs of interruptions

In real-world settings, execution of retrieved intentions must often be briefly delayed until an ongoing activity is completed (delayed-execute prospective memory tasks). Further, in demanding work settings, the ongoing activity itself can be interrupted. Experiment 1 examined the effects of the delay length (5, 15, 40 s), the presence of an interruption within that delay, and the length of the interruption on prospective memory performance. Delay length did not significantly affect performance, but interruptions produced significant decrements in performance relative to a delay alone. The length of the interruptions (10 vs. 20 s) did not significantly affect performance. Experiment 2 replicated the negative effects of interruptions, and found that these effects could be overcome with a simple external mnemonic. We suggest that in demanding work environments where interruptions are likely, external cues are advisable, especially where prospective memory failures have critical consequences. Copyright © 2004 John Wiley & Sons, Ltd.     

Individual Differences in Reward-Based Learning Predict Fluid Reasoning Abilities

The ability to reason and problem-solve in novel situations, as measured by the Raven's Advanced Progressive Matrices (RAPM), is highly predictive of both cognitive task performance and real-world outcomes. Here we provide evidence that RAPM performance depends on the ability to reallocate attention in response to self-generated feedback about progress. We propose that such an ability is underpinned by the basal ganglia nuclei, which are critically tied to both reward processing and cognitive control. This hypothesis was implemented in a neurocomputational model of the RAPM task, which was used to derive novel predictions at the behavioral and neural levels. These predictions were then verified in one neuroimaging and two behavioral experiments. Furthermore, an effective connectivity analysis of the neuroimaging data confirmed a role for the basal ganglia in modulating attention. Taken together, these results suggest that individual differences in a neural circuit related to reward processing underpin human fluid reasoning abilities.     

The Effect of Prior Fear Levels on UCS-expectancy Ratings to a Fear-relevant Stimulus

This study investigated the effect of levels of prior fear to a fear-relevant stimulus on UCS expectancy ratings in a threat conditioning procedure. The results suggested that UCS-expectancy ratings are independently influenced by both the nature of the stimulus (whether it is fear-relevant or fear-irrelevant) and the level of prior fear to the stimulus. Furthermore, significantly higher UCS-expectancy levels caused by prior fear and stimulus type were accompanied in some stages of the experiment by greater magnitudes of skin conductance responses during the stimulus.     

Adolescent Development and the Emergence of Sexuality

Adolescence is a time of significant opportunity and significant challenge. Challenges can be difficult for some adolescents, which may result in problems that are expressed as affective disturbances or by the adolescent's participation in risk-taking behaviors. This review emphasizes the changes in biopsychosocial development during adolescence. We specifically address aspects of individual change during the adolescent decade (e.g., biological, cognitive, psychosocial, and sexual development) as well as the effects of context on normal development and responses to challenges during this period. Predispositions or vulnerabilities present prior to a developmental transition may be exacerbated by the transition. Adolescents can become healthy adults with the encouragement to develop gradually by limiting the simultaneous changes they experience, where possible, and by supporting healthy development through developmentally appropriate activities and supportive relationships with adults and peers.     

Retrospective Revaluation and Inhibitory Associations: Does Perceptual Learning Modulate our Perception of the Contingencies Between Events?

The reported experiments seek to reconcile the conflict between proposed explanations of retrospective revaluation of contingency judgements in experiments with humans (e.g. Dickinson & Burke, 1996) and those of a perceptual learning phenomenon discovered in rats (Espinet, Iraola, Bennett, &Mackintosh, 1995). The experiments employ a medical diagnosis scenario, in which subjects are asked to judge whether particular symptoms signal the presence or absence of a fictitious disease. In Experiment 1, following alternating exposure to pairs of symptoms, AX and BX, subjects were informed that symptom A was predictive of illness. As a result of this training, subjects rated symptom B as predictive of the absence of the illness. In Experiment 2, a possible mechanism behind this effect was considered. In particular, it was established that pre-exposure in which the AX pair reliably preceded the BX pair produced the same pattern of results as those shown in Experiment 1. In contrast, when the order of pairs was reversed, so that BX reliably preceded AX, the reduction in ratings for symptom B was not obtained. Several extant associative theories are discussed, but none are found to account adequately for this pattern of results. To overcome these inadequacies, a parsimonious theory is suggested that explains all the effects observed in these experiments.