Cortical potentials evoked by confirming and disconfirming feedback following an auditory discrimination

Vertex potentials elicited by visual feedback (signals following an auditory intensity discrimination have been studied with eight Ss. Feedback signals which confirmed the prior sensory decision elicited small P3s, while disconfirming, feedback elicited P3s that were larger. On the average, the latency of P3 was also found to increase with increasing disparity between the judgment and. the feedback information. These effects were part bf an overall dichotomy in waveshape following confirming vs disconforming feedback. These findings are incorporated in a general model of the role of P3 in perceptual decision making.     

Spatial frequency comparisons of rotated gratings

Reaction time for determining if two square-wave gratings are the same or different is a bimodal function of the relative angular separation (RAS) between them. Response time peaks at 60° and 120° separation and drops siguificantly at approximately 90°, provided that the gratings being compared are of the same spatial frequency. This pattern of results is not in line with those previously reported for more complex figures, nor may it be attributed to any “oblique effect,” since the same function is obtained with the comparison gratings placed at different retinal orientations. One possible explanation is that orthogonally tuned orientation channels interact in a facilitatory fashion in the human visual system.     

Regulatory fit as input for stop rules

Three experiments show that the motivational effects of regulatory fit (consistency between regulatory state and strategic means) are context dependent. With no explicit decision rule about when to stop (Experiment 1) or an explicit enjoyment stop rule (Experiments 2 and 3), participants exerted more effort on tasks when experiencing regulatory fit than when experiencing regulatory nonfit. With an explicit sufficiency stop rule (Experiments 2 and 3), participants exerted less effort when experiencing regulatory fit than when experiencing regulatory nonfit. The interactive effect of regulatory fit and stop rules can be explained by misattribution of rightness feelings from regulatory fit; the effect was eliminated by drawing participants' attention to an earlier event as a source of rightness feelings (Experiments 1 and 3).     

Behavioral assessment of impulsivity: a comparison of children with and without attention deficit hyperactivity disorder

We conducted a brief computer-based assessment involving choices of concurrently presented arithmetic problems associated with competing reinforcer dimensions to assess impulsivity (choices controlled primarily by reinforcer immediacy) as well as the relative influence of other dimensions (reinforcer rate, quality, and response effort), with 58 children. Results were compared for children with attention deficit hyperactivity disorder (ADHD) who were and were not receiving medication, and with typically developing children without ADHD. Within-subject and between-groups analyses of the ordinal influence of each of the reinforcer dimensions were conducted using both time- and response-allocation measures. In general, the choices of children with ADHD were most influenced by reinforcer immediacy and quality and least by rate and effort, suggesting impulsivity. The choices of children in the non-ADHD group were most influenced by reinforcer quality, and the influence of immediacy relative to the other dimensions was not statistically significant. Results are discussed with respect to the implications for assessment and treatment of ADHD.     

Remembrance of remembrance past

Arnold and Lindsay (2002) found that individuals more often failed to remember they had previously recalled an item if that item had been cued in a qualitatively different way on two recall occasions: the "forgot-it-all-along" (FIA) effect. Experiment 1 was designed to determine if the FIA effect arises because participants incorrectly believe they have not been previously tested for an item, or because they incorrectly believe they have failed to recall the item when previously tested. Experiment 2 measured participants' confidence in their incorrect prior-recall judgements, and Experiment 3 tested participants' ability to "recover" their previous recollection when the prior-recall context was restored. Results indicated that participants usually believed they had not previously been cued for the items they failed to remember previously recalling; they were often confident in their incorrect judgements of prior non-remembering; and re-introducing the context of prior remembering sometimes enabled them to recapture their memories of previous recall.     

Slaves, embryos, and nonhuman animals: moral status and the limitations of common morality theory

Common morality theory must confront apparent counterexamples from the history of morality, such as the widespread acceptance of slavery in prior eras, that suggest core norms have changed over time. A recent defense of common morality theory addresses this problem by drawing a distinction between the content of the norms of the common morality and the range of individuals to whom these norms apply. This distinction is successful in reconciling common morality theory with practices such as slavery, but only at the cost of underscoring the limits of common morality theory, in particular its inability to resolve disputes about the moral status of entities. Given that many controversies in bioethics center on the disputed status of various entities, such as embryos and nonhuman animals, this is an important limitation. Nonetheless, common morality theory still can be a useful resource in diminishing moral conflict on issues that do not involve disputes over moral status.     

Enhancements and justice: problems in determining the requirements of justice in a genetically transformed society

There is a concern that genetic engineering will exacerbate existing social divisions and inequalities, especially if only the wealthy can afford genetic enhancements. Accordingly, many argue that justice requires the imposition of constraints on genetic engineering. However, it would be unwise to decide at this time what limits should be imposed in the future. Decision makers currently lack both the theoretical tools and the factual foundation for making sound judgments about the requirements of justice in a genetically transformed society. Moreover, focusing on the uncertain inequities of the future may result in failure to give priority to more pressing inequities of the present. Especially in a country that recently has enacted tax legislation that will widen existing wealth disparities, concern about the distant threat of a genetic aristocracy appears misplaced.     

Short-term retention during a simultaneous detection task

Subjects were required to perform a short-term memory task and a signal detection task, both individually and simultaneously. Memory performance was impaired only when the signals in the detection task were difficult to detect. The impairment in memory was restricted to items which appeared in the early positions of the list to be remembered. Detection performance was unaffected by the simultaneous task requirement and there was no correlation between performance on the two tasks when both were performed together. The results suggest that the difficulties Ss have when they attempt to perform several tasks at the same time may be due to limitations in the processes responsible for storing and retrieving information rather than those involved in the perceptual analysis of the incoming material.