Metacognitive bias resulting from trade-off between local and global motion signals.

Visual confidence generally depends on performance in targeted perceptual tasks. However, it remains unclear how factors unrelated to performance affect confidence. Given the hierarchical nature of visual processing, both local and global stimulus features can influence confidence, but their strengths of influence remain unknown. To address this question, we independently manipulated the local contrast signals and the global coherence signals in a multiple-aperture motion pattern. The drifting-Gabor elements were individually manipulated to give rise to a coherent global motion percept. In both dichotomous direction-discrimination task (Experiment 1) and analog direction-judgment task (Experiment 2), we found stimulus-dependent biases in metacognition despite matched perceptual performance. Specifically, participants systematically gave higher confidence ratings to an incoherent pattern with clear elements (i.e., strong local but weak global signals) than a coherent pattern with noisy elements (i.e., weak local but strong global signals). We did not find any systematic effects of local/global stimulus features on metacognitive sensitivity. Model comparisons show that variation in local/global signals in the stimulus should be considered a factor influencing confidence, even after controlling for the effects of performance. Our results suggest that the metacognitive system, when generating confidence for a perceptual task, puts more weights on local than global signals.

University students' diurnal learning-directed behavior is strongly influenced by school start times with implications for grades.

STUDY OBJECTIVES: School start times impose constraints on sleep-wake timing that may influence academic achievement. We used large university archived datasets to test the hypothesis that larger differences in timing of students' diurnal learning behavior on school days relative to non-school days would be associated with lower grades. METHODS: Diurnal learning-directed behavior was examined in 33 645 university students by analyzing their learning management system (LMS) login rhythm. We tested the associations between the phase-difference in students' behavioral rhythm on school days versus non-school days with grade point average, LMS-login phase on non-school days (LMS-login chronotype), and school start time. We also tested the chronotype-dependent effects of school start times on diurnal behavior to determine whether students obtained better course grades when their first class of the day was in synch with their LMS-login chronotype. RESULTS: Students whose LMS-login rhythm was more than 2 hours earlier on school days had significantly lower grades than their peers. The change in LMS-login phase was larger in students with a later LMS-login chronotype and for earlier school start times. Minimal changes in LMS-login phase and higher course grades were observed when students' first class of the day was aligned with their LMS-login chronotype. CONCLUSIONS: Our findings demonstrate that school start times have a profound impact on students' diurnal learning behavior with implications for grades. Universities can potentially improve learning by starting school later to minimize differences in diurnal learning behavior between school days and non-school days.

The efficiency of visual search for a frequently changed target is preserved in older adults.

Visual search is a psychological function integral to most people's daily lives. The extent to which visual search efficiency, and in particular the ability to use top-down attention in visual search, changes across the lifespan has been the focus of ongoing research. Here we sought to understand how the ability to frequently and dynamically change the target in a conjunction search task was affected by ageing. To do this, we compared visual search performance of a group of younger and older adults under conditions in which the target type was determined by a cue and could change on trial-to-trial basis (Intermixed), versus when the target type was fixed for a block of trials (Blocked). Although older adults were overall slower at the conjunction visual search task, and both groups were slower in the Intermixed compared with the Blocked Condition, older adults were not disproportionately affected by the Intermixed relative to the Blocked conditions. These results indicate that the ability to frequently change the target of visual search is preserved in older adults. This conclusion is consistent with an emerging consensus that many aspects of visual search and top-down contributions to it are preserved across the lifespan. It is also consistent with a growing body of work which challenges the neurocognitive theories of ageing that predict sweeping deficits in complex top-down components of cognition.

Searching for emotion: A top-down set governs attentional orienting to facial expressions.

Research indicates that humans orient attention toward facial expressions of emotion. Orienting to facial expressions has typically been conceptualised as due to bottom-up attentional capture. However, this overlooks the contributions of top-down attention and selection history. In the present study, across four experiments, these three attentional processes were differentiated using a variation of the dot-probe task, in which participants were cued to attend to a happy or angry face on each trial. Results show that attention toward facial expressions was not exclusively driven by bottom-up attentional capture; instead, participants could shift their attention toward both happy and angry faces in a top-down manner. This effect was not found when the faces were inverted, indicating that top-down attention relies on holistic processing of the face. In addition, no evidence of selection history was found (i.e., no improvement on repeated trials or blocks of trials in which the task was to orient to the same expression). Altogether, these results suggest that humans can use top-down attentional control to rapidly orient attention to emotional faces.