Busy perceivers and ineffective suppression goals: a critical role for distracter thoughts.

With limited cognitive resources, suppressing thoughts can be ineffective. The detrimental effects of cognitive load on suppression have typically been attributed to increased accessibility of avoided thoughts. However, little research has examined distracter thoughts and their contribution to these effects. In three studies, participants pursued suppression goals related to social judgments (e.g., avoid negative thoughts about a target's performance) with sufficient or diminished cognitive resources. Compared to suppressors not under cognitive load, suppressors under load drew more negative social inferences when pursuing a negative suppression goal and more positive inferences under a positive suppression goal; load did not similarly disrupt a concentration goal (i.e., focus on positive thoughts). Across studies, load reduced high-quality oppositely valenced distracter thoughts, and these distracter thoughts mediated the detrimental effects of load on social inferences. The discussion focuses on mechanisms underlying the effects of load on suppression, implications, and future directions for research on ironic processes.

Toward the improvement of image-guided interventions for minimally invasive surgery: three factors that affect performance.

OBJECTIVES: The objectives were to measure the impact of specific features of imaging devices on tasks relevant to minimally invasive surgery (MIS) and to investigate cognitive and perceptual factors in such tasks. BACKGROUND: Although image-guided interventions used in MIS provide benefits for patients, they pose drawbacks for surgeons, including degraded depth perception and reduced field of view (FOV). It is important to identify design factors that affect performance. METHOD: In two navigation experiments, observers fed a borescope through an object until it reached a target. Task completion time and object shape judgments were measured. In a motion perception experiment, observers reported the direction of a line that moved behind an aperture. A motion illusion associated with reduced FOV was measured. RESULTS: Navigation through an object was faster when a preview of the object's exterior was provided. Judgments about the object's shape were more accurate with a preview (compared with none) and with active viewing (compared with passive viewing). The motion illusion decreased with a rectangular or rotating octagonal viewing aperture (compared with circular). CONCLUSIONS: Navigation performance may be enhanced when surgeons develop a mental model of the surgical environment, when surgeons (rather than assistants) control the camera, and when the shape of the image is designed to reduce visual illusions. APPLICATION: Unintentional contact between surgical tools and healthy tissues may be reduced during MIS when (a) visual aids permit surgeons to maintain a mental model of the surgical environment, (b) images are bound by noncircular apertures, and (c) surgeons manually control the camera.

Motion extrapolation of car-following scenes in younger and older drivers.

OBJECTIVE: The objective was to determine whether distortions occur in motion extrapolation of car-following scenes in younger and older drivers. BACKGROUND: Drivers cannot see an entire traffic scene clearly with one glance. They must extrapolate the motion of surrounding vehicles while scanning other parts of the scene. Further, abilities relevant to motion extrapolation decline with age. Thus, it is important to evaluate age differences in motion extrapolation. METHOD: Displays simulated car-following scenes. After an interruption, the scene reappeared at the correct position in its trajectory or at a position that was more advanced or less advanced than the correct position. Drivers reported whether the scene reappeared at the correct position. RESULTS: When the virtual self moved faster than the lead car, older drivers' judgments were biased toward less advanced reappearance positions. Younger drivers' judgments were biased toward more advanced positions. The implication is that older drivers extrapolated the motion slower than did younger drivers. CONCLUSION: Distortions occurred in motion extrapolation of car-following scenes, and age differences occurred in such distortions. APPLICATION: Potential applications of this research include traffic safety. Age differences in motion extrapolation are useful to consider in differential accident patterns of younger and older drivers. Future research should investigate the relationship between accidents and the ability to extrapolate motion, particularly during driver distractions.