A long-standing question in vision science is whether individual differences in visual performance reflect a general visual ability or a set of largely task-specific processes. Previous studies have often reported weak associations across heterogeneous perceptual tasks, challenging the idea of a common visual factor. Here, we asked whether shared variance becomes more evident when visual tasks are conceptually and procedurally similar. One hundred fifty-eight adults completed eight low-level acuity and hyperacuity paradigms implemented in FrACT10: single letter, Landolt C, tumbling E, row of optotypes, flanking rings, frame ring, Vernier two-line, and Vernier three-line tasks. After outlier exclusion, analyses were conducted on 132 participants. Within-session test–retest reliability was moderate for most tasks. Pairwise correlations revealed a broad positive manifold: all correlations were positive, 27 of 28 survived false-discovery-rate correction, and Bayesian analyses provided strong evidence for nonzero associations in most task pairs. However, association strength depended strongly on task similarity, with robust correlations among optotype-based tasks and weaker links between optotype and Vernier paradigms. Exploratory factor analyses indicated substantial shared covariance but failed to support a stable latent structure: A one-factor model fit poorly, whereas two-factor and three-factor solutions produced improper estimates. These findings support an intermediate account of visual individual differences. Visual performance is neither fully independent across tasks nor reducible to a strong general visual factor; instead, commonality appears partial, task-dependent, and shaped by the composition of the task battery. The data, data dictionary, analysis code, and rendered analysis reports that support the findings of this study are available on OSF ( https://doi.org/10.17605/OSF.IO/AKSN3 ). The study materials are described in the Method section and are based on FrACT10. This study was not preregistered.
Existing approaches to measure the time needed to process a single stimulus have confounded the measure with other time-consuming processes, such as initiation of the response, and neglect the massively parallel processing abilities of the visual system. Conversely, traditional set-size manipulations in visual search yield flawed estimates of stimulus-processing time, mainly because the number of actually processed stimuli is typically unknown. We have recently developed the systematic-search paradigm, a visual-search paradigm that overcomes this limitation and potentially provides a valid measure of stimulus-processing time. Its core idea is to bring the order of search under experimental control, so that the number of processed stimuli is determined by the position of the target on the current trial. We then extract the slope of the linear function relating target position (and therefore the number of processed stimuli) to response times. With this approach, all extraneous processing times are relegated to the intercept of the function. The present study provides a further validation of this slope-measure by showing that it reflects the complexity of the visual stimuli (Exp. 1), but is robust against changes in the complexity of the response (Exp. 2). All raw data, analysis code, preregistrations, and research materials are available online ( https://osf.io/42mxh/ ). In both experiments, we report how we determined our sample size, all data exclusions (if any), all manipulations, and all measures in the study. The experiments’ designs and analyses were preregistered. All trial-level raw data, analysis code, preregistrations and research materials are available online ( https://osf.io/42mxh/ ). Direct links to the preregistrations are https://osf.io/tbk8s/ (Exp. 1) and https://osf.io/va98q/ (Exp. 2).
When observing a person with direct gaze but a horizontally averted head posture, attention often shifts opposite to head direction (overshoot effect). We investigated whether this effect generalizes to vertical head movements and whether it depends on gaze direction information. Across four experiments, centrally presented faces shifted dynamically to averted head positions before a target appeared at a location congruent or incongruent with head direction. Vertical head movements (Experiments 1 and 2) produced head-congruency effects, which were stronger when the eyes were closed. In contrast, horizontal head movements (Experiments 3 and 4) produced classic overshoot effects, which surprisingly were amplified when the eyes were closed. Thus, direct gaze attenuated head-cueing effects but did not alter their direction. Overall, these findings reveal dimensional asymmetries in social attention and demonstrate that gaze-head integration considers spatial context. Implications for hierarchical, holistic, and predictive cue-integration accounts are discussed. All four experiments were preregistered on the Open Science Framework (OSF; Experiment 1: https://osf.io/qds4x ; Experiment 2: https://osf.io/d6rwe ; Experiment 3: https://osf.io/xe9a6 ; Experiment 4: https://osf.io/3pq49 ). Materials, experimental scripts, stimuli, raw data, and analysis scripts underlying the reported results are publicly available at https://osf.io/aq7zf/ and https://osf.io/j96fx/
We examined whether bilingual readers can extract language membership information from multiple words at once. Dutch–English bilinguals completed a lexical decision task in a flankers paradigm, with viewing times manipulated either to constrain (50 ms) or allow (170 ms) sequential reading. The findings revealed reliable congruency effects (i.e., slower on the central target word when the flankers were presented in a different language than when they were presented in the same language) in 170 ms, but this effect disappeared when the stimulus was presented for 50 ms. The pattern indicates limited parallel extraction of language membership information across multiple words. The data that support the findings of this study are openly available in OSF ( https://doi.org/10.17605/OSF.IO/MX2NU ). The stimuli, trial-level data for both experiments, and the analysis code are provided in this repository link. The study was not preregistered.
Keeping track of multiple moving objects across dynamic real-world scenarios such as driving, team sports, or crowded social environments is a fundamental challenge for visual attention. We have previously demonstrated that as the number of tracked objects increases, the strength of attentional facilitation allocated to each individual object decreases, limiting tracking success. It is also well established that beyond the number of tracked objects, faster-moving objects and objects embedded amongst higher numbers of distractors are more difficult to track. Are these effects on tracking difficulty also mediated by less effective allocation of attention to tracked targets as in the case of tracking more targets? If so, one should expect the strength of attentional modulation to drop systematically with increasing speed and total number of moving stimuli. In two experiments (total n = 70), participants were instructed to track moving targets amongst identical distractors while we manipulated object speed (Experiment 1) and number (Experiment 2). As expected, tracking performance declined with both manipulations. However, steady-state visual evoked potentials (SSVEPs) recorded during successful tracking revealed that attentional enhancement of tracked targets compared with distractors did not drop with increasing speed or object number. In summary, bottom-up changes in the stimulus display and top-down attentional manipulations affect tracking performance in independent ways, with the balance between strength of attentional allocation and bottom-up demands of the task determining successful tracking. The allocation of attention itself seems to be determined exclusively by top-down goals rather than being reactive to bottom-up display characteristics. Keeping track of multiple moving objects is fundamental to navigating dynamic real-world scenarios. This ability is accomplished through multifocal attentional selection, which weakens as the number of tracked targets increases. This study asks whether other stimulus manipulations increase tracking difficulty by diluting attentional allocation. Using steady-state visual evoked potentials to measure selective attention during tracking, we demonstrate that both increases in speed and distractor number impair performance, but they do not affect attentional enhancement of targets relative to distractors. This suggests that top-down attentional control operates independently from bottom-up demands.
