Learning to optimize speed, accuracy, and energy expenditure: a framework for understanding speed-accuracy relations in goal-directed aiming

Over the last century, investigators have developed a number of models to explain the relation between speed and accuracy in target-directed manual aiming. The models vary in the extent to which they stress the importance of feedforward processes and the online use of sensory information (see D. Elliott, W. F. Helsen, & R. Chua, 2001, for a recent review). A common feature of those models is that the role of practice in optimizing speed, accuracy, and energy expenditure in goal-directed aiming is either ignored or minimized. The authors present a theoretical framework for understanding speed-accuracy tradeoffs that takes into account the strategic, trial-to-trial behavior of the performer. The strategic behavior enables individuals to maximize movement speed while minimizing error and energy expenditure.     

On the neurobiological investigation of language understanding in context

There are two significant problems in using functional neuroimaging methods to study language. Improving the state of functional brain imaging will depend on understanding how the dependent measure of brain imaging differs from behavioral dependent measures (the "dependent measure problem") and how the activation of the motor system may be confounded with non-motor aspects of processing in certain experimental designs (the "motor output problem"). To address these problems, it may be necessary to shift the focus of language research from the study of linguistic competence to the understanding of language use. This will require investigations of language processing in full multi-modal and environmental context, monitoring of natural behaviors, novel experimental design, and network-based analysis. Such a combined naturalistic approach could lead to tremendous new insights into language and the brain.     

Medical ethicists, human curiosities, and the new media midway

Medical ethicists have assumed a role in justifying public voyeurism of human "curiosities." This role has precedent in how scientists and natural philosophers once legitimized the marketing of museums of "human curiosities." At the beginning of the twentieth century, physicians dissociated themselves from entrepreneurial displays of persons with anomalies, and such commercial exhibits went into decline. Today, news media, principally on television, promote news features about persons that closely resemble the nineteenth century exhibits of human curiosities. Reporters solicit medical ethicists for soundbites to affirm the newsworthiness and propriety of public voyeurism of these medical stories. Ethicists' soundbites are usually ambiguous or self-evident and rarely enable viewers to morally engage the issues. The precedent of early twentieth century physicians disengaging from such exploitive public shows is a useful example for medical ethics.     

Psychological sequelae of remote exposure to the September 11th terrorist attacks in Canadians with and without panic

The purpose of the present investigation was to examine the psychological impact of remote exposure to the events and aftermath of the terrorist attacks in the USA on September 11th, 2001, and to assess what differences, if any, exist between individuals classified with probable panic disorder and those without. Telephone interviews were conducted with 122 residents of the capital city of the Canadian prairie province of Saskatchewan in spring 2002 in order to gather information regarding current mood, fears and avoidance behaviours as well as current post-traumatic stress disorder symptoms specific to September 11th. Consistent with previous findings and despite the remote nature of exposure, results indicated that the psychological well-being and behaviour of participants with probable panic disorder was more adversely affected by the events and aftermath of September 11th than those without panic disorder. These results suggest that remote viewing of traumatic events can have a significant and lingering impact on psychological well-being and behaviour and that these effects are more pronounced in those with panic disorder. Implications of the findings and future research directions are discussed.     

School-year employment among high school students: effects on academic, social, and physical functioning

This study describes the effects of different weekly work intensity levels on adolescent functioning in a sample of 3,083 high school students in rural South Texas, where economically disadvantaged and Hispanic youth are heavily represented. Anonymous surveys were conducted in 10th- and 12th-grade students' classrooms in 1995. The following effects were associated with long hours of weekly employment during the school year: (1) decreased performance/engagement in school and satisfaction with amount of leisure time, and (2) increased health risk behaviors and psychological stress. The effects of school-year work on academic factors and health behaviors differed by grade, but not by race/ethnicity, parent education, or race/ethnicity and parent education considered together. It was concluded that parents and professionals should continue to monitor the number of weekly hours that students work during the school year.     

Working memory for visual features and conjunctions in schizophrenia

The visual working memory (WM) storage capacity of patients with schizophrenia was investigated using a change detection paradigm. Participants were presented with 2, 3, 4, or 6 colored bars with testing of both single feature (color, orientation) and feature conjunction conditions. Patients performed significantly worse than controls at all set sizes but demonstrated normal feature binding. Unlike controls, patient WM capacity declined at set size 6 relative to set size 4. Impairments with subcapacity arrays suggest a deficit in task set maintenance: Greater impairment for supercapacity set sizes suggests a deficit in the ability to selectively encode information for WM storage. Thus, the WM impairment in schizophrenia appears to be a consequence of attentional deficits rather than a reduction in storage capacity.     

Sexually selective cognition: beauty captures the mind of the beholder

Across 5 experimental studies, the authors explore selective processing biases for physically attractive others. The findings suggest that (a). both male and female observers selectively attend to physically attractive female targets, (b). limiting the attentional capacity of either gender results in biased frequency estimates of attractive females, (c). although females selectively attend to attractive males, limiting females' attentional capacity does not lead to biased estimates of attractive males, (d). observers of both genders exhibit enhanced recognition memory for attractive females but attenuated recognition for attractive males. Results suggest that different mating-related motives may guide the selective processing of attractive men and women.     

Secure and defensive high self-esteem

Long-standing theories have suggested high self-esteem (SE) can assume qualitatively different forms that are related to defensiveness. The authors explored whether some high-SE individuals are particularly defensive because they harbor negative self-feelings at less conscious levels, indicated by low implicit SE. In Study 1, participants high in explicit SE but low in implicit SE showed the highest levels of narcissism--an indicator of defensiveness. In Studies 2 and 3, the correspondence between implicit and explicit SE predicted defensive behavior (in-group bias in Study 2 and dissonance reduction in Study 3), such that for high explicit-SE participants, those with relatively low implicit SE behaved more defensively. These results are consistent with the idea that high SE can be relatively secure or defensive.     

Bimanual interference associated with the selection of target locations

Four experiments were conducted to identify the locus of interference observed during the preparation of bimanual reaching movements. Target locations were specified by color, and the right-hand and left-hand targets could be either the same or a different color. Movements of different amplitudes (Experiment 1) or different directions (Experiment 2) to targets of the same color were initiated more quickly than symmetric movements to targets of different colors. These results indicate that costs observed during bimanual movements arise during target selection rather than during motor programming. Experiments 3 and 4 further examined the interference associated with target selection. Reaction time costs were found with unimanual movements when the target was presented among distractors associated with responses for the other hand. Interference observed during bimanual reaching appears to reflect difficulty in segregating the response rules assigned to each hand.     

Trial spacing is a determinant of cue interaction

Four conditioned lick suppression experiments with rats examined the effect of trial spacing on cue interaction. Experiments 1 and 2 found overshadowing to be eliminated with massed compound stimulus-outcome pairings and the usual trial spacing effect to be reversed with compound acquisition trials. Experiment 3 found that whether acquisition compound-outcome pairings were massed or spaced determined the effect of posttraining extinction treatment. Extinction of the overshadowing cue reduced responding following massed training and increased responding following spaced training. Extinction of the context decreased responding following massed training. Experiment 4 found the conditioning and devaluation results to be associative and stimulus specific. These results are in accord with the extended comparator hypothesis (J. C. Denniston, H. I. Savastano, & R. R. Miller, 2001).