The time course of attentional and oculomotor capture reveals a common cause

Eye movements are often misdirected toward a distractor when it appears abruptly, an effect known as oculomotor capture. Fundamental differences between eye movements and attention have led to questions about the relationship of oculomotor capture to the more general effect of sudden onsets on performance, known as attentional capture. This study explores that issue by examining the time course of eye movements and manual localization responses to targets in the presence of sudden-onset distractors. The results demonstrate that for both response types, the proportion of trials on which responses are erroneously directed to sudden onsets reflects the quality of information about the visual display at a given point in time. Oculomotor capture appears to be a specific instance of a more general attentional capture effect. Differences and similarities between the two types of capture can be explained by the critical idea that the quality of information about a visual display changes over time and that different response systems tend to access this information at different moments in time

Local form interference in biological motion perception

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Failure of Intuition When Choosing Whether to Invest in a Single Goal or Split Resources Between Two Goals

In a series of related experiments, we asked people to choose whether to split their attention between two equally likely potential tasks or to prioritize one task at the expense of the other. In such a choice, when the tasks are easy, the best strategy is to prepare for both of them. As difficulty increases beyond the point at which people can perform both tasks accurately, they should switch strategy and focus on one task at the expense of the other. Across three very different tasks (target detection, throwing, and memory), none of the participants switched their strategy at the correct point. Moreover, the majority consistently failed to modify their strategy in response to changes in task difficulty. This failure may have been related to uncertainty about their own ability, because in a version of the experiment in which there was no uncertainty, participants uniformly switched at an optimal point

Attentional load interferes with target localization across saccades

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Driving forces in free visual search : An ethology

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The eye that binds : Feature integration is not disrupted by saccadic eye movements

Open Access via the Springer Compact Agreement FundRef James S. McDonnell Foundation The data for both experiments, as well as a file containing the stimuli of experiment 1 are available at https://osf.io/k49mf/, where experiment 1 was also preregistered. Acknowledgements: The authors thank Johanna Barclay, Rachel Buhler, Qjan Li, Jesus Rendon, Caitlyn Smith, Alejandro Suarez and Vasilena Voynikova, who collected the data of experiment 2 as part of a group project.Peer reviewedPublisher PD

The role of attention in eye-movement awareness

People are unable to accurately report on their own eye movements most of the time. Can this be explained as a lack of attention to the objects we fixate? Here, we elicited eye-movement errors using the classic oculomotor capture paradigm, in which people tend to look at sudden onsets even when they are irrelevant. In the first experiment, participants were able to report their own errors on about a quarter of the trials on which they occurred. The aim of the second experiment was to assess what differentiates errors that are detected from those that are not. Specifically, we estimated the relative influence of two possible factors: how long the onset distractor was fixated (dwell time), and a measure of how much attention was allocated to the onset distractor. Longer dwell times were associated with awareness of the error, but the measure of attention was not. The effect of the distractor identity on target discrimination reaction time was similar whether or not the participant was aware they had fixated the distractor. The results suggest that both attentional and oculomotor capture can occur in the absence of awareness, and have important implications for our understanding of the relationship between attention, eye movements, and awareness

Human visual search behaviour is far from ideal

Evolutionary pressures have made foraging behaviours highly efficient in many species. Eye movements during search present a useful instance of foraging behaviour in humans. We tested the efficiency of eye movements during search using homogeneous and heterogeneous arrays of line segments. The search target is visible in the periphery on the homogeneous array, but requires central vision to be detected on the heterogeneous array. For a compound search array that is heterogeneous on one side and homogeneous on the other, eye movements should be directed only to the heterogeneous side. Instead, participants made many fixations on the homogeneous side. By comparing search of compound arrays to an estimate of search performance based on uniform arrays, we isolate two contributions to search inefficiency. First, participants make superfluous fixations, sacrificing speed for a perceived (but not actual) gain in response certainty. Second, participants fixate the homogeneous side even more frequently than predicted by inefficient search of uniform arrays, suggesting they also fail to direct fixations to locations that yield the most new information

Visual search habits and the spatial structure of scenes

Acknowledgement This research was supported by the Economic and Social Research Council (ESRC, ES/S016120/1). Katie Black collected the data for Experiment 2 while undertaking a Bradshaw-Eagle Undergraduate Research Scholarship from the Applied Vision Association. We would like to thank her, and also Ana Sima, who collected the data for Experiment 1.Peer reviewedPublisher PD

Inefficient search strategies in simulated hemianopia.

We investigated whether healthy participants can spontaneously adopt effective eye movement strategies to compensate for information loss similar to that experienced by patients with damage to visual cortex (hemianopia). Visual information in 1 hemifield was removed or degraded while participants searched for an emotional face among neutral faces or a line tilted 45° to the right among lines of varying degree of tilt. A bias to direct saccades toward the sighted field was observed across all 4 experiments. The proportion of saccades directed toward the “blind” field increased with the amount of information available in that field, suggesting fixations are driven toward salient visual stimuli rather than toward locations that maximize information gain. In Experiments 1 and 2, the sighted-field bias had a minimal impact on search efficiency, because the target was difficult to find. However, the sighted-field bias persisted even when the target was visually distinct from the distractors and could easily be detected in the periphery (Experiments 3 and 4). This surprisingly inefficient search behavior suggests that eye movements are biased to salient visual stimuli even when it comes at a clear cost to search efficiency, and efficient strategies to compensate for visual deficits are not spontaneously adopted by healthy participants