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Perceived stress and satisfaction with social support were assessed in 318 men participating in a prostate-specific antigen (PSA) screening program. We predicted that high stress would be associated with high PSA and high social support with low PSA. We also predicted a Stress x Support interaction (buffering). Hypothesized main effects were confirmed and were not explained by recency of previous rectal examinations or current urinary symptoms. There was no evidence of buffering. Stress and social support were not associated with results of digital rectal examinations. These findings raise the possibility that psychosocial factors promote prostate disease through direct physiologic pathways. However, it is also possible that the data reflect effects of stress on health-related behaviors or that stress scores were affected by participants' anticipation of prostate problems on the basis of prior PSA tests or symptoms. 相似文献
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In previous studies of saccadic targeting, the issue how visually guided saccades to unambiguous targets are programmed and executed has been examined. These studies have found different degrees of guidance for saccades depending on the task and task difficulty. In this study, we use ideal-observer analysis to estimate the visual information used for the first saccade during a search for a target disk in noise. We quantitatively compare the performance of the first saccadic decision to that of the ideal observer (ie absolute efficiency of the first saccade) and to that of the associated final perceptual decision at the end of the search (ie relative efficiency of the first saccade). Our results show, first, that at all levels of salience tested, the first saccade is based on visual information from the stimulus display, and its highest absolute efficiency is approximately 20%. Second, the efficiency of the first saccade is lower than that of the final perceptual decision after active search (with eye movements) and has a minimum relative efficiency of 19% at the lowest level of saliency investigated. Third, we found that requiring observers to maintain central fixation (no saccades allowed) decreased the absolute efficiency of their perceptual decision by up to a factor of two, but that the magnitude of this effect depended on target salience. Our results demonstrate that ideal-observer analysis can be extended to measure the visual information mediating saccadic target-selection decisions during visual search, which enables direct comparison of saccadic and perceptual efficiencies. 相似文献