Inefficient search strategies in simulated hemianopia

TY - JOUR

T1 - Inefficient search strategies in simulated hemianopia

AU - Nowakowska, Anna

AU - Clarke, Alasdair D. F.

AU - Sahraie, Arash

AU - Hunt, Amelia R

N1 - Acknowledgements Anna Nowakowska is supported by an ESRC doctoral studentship. A James S McDonnell scholar award to Amelia R. Hunt also provided financial support. We are grateful to Edvinas Pilipavicius and Juraj Sikra for data collection. We also wish to thank W. Joseph MacInnes for help with programming the experiment and Paul Hibbard for help with filtering the faces.

PY - 2016/11

Y1 - 2016/11

N2 - 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 one 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 towards the sighted field was observed across all four experiments. The proportion of saccades directed towards the “blind” field increased with the amount of information available in that field, suggesting fixations are driven towards salient visual stimuli rather than towards 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 behaviour 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.

AB - 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 one 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 towards the sighted field was observed across all four experiments. The proportion of saccades directed towards the “blind” field increased with the amount of information available in that field, suggesting fixations are driven towards salient visual stimuli rather than towards 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 behaviour 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.

KW - visual search

KW - optimality

KW - blindsight

KW - hemianopia

U2 - 10.1037/xhp0000250

DO - 10.1037/xhp0000250

M3 - Article

VL - 42

SP - 1858

EP - 1872

JO - Journal of Experimental Psychology: Human Perception and Performance

JF - Journal of Experimental Psychology: Human Perception and Performance

SN - 0096-1523

IS - 11

ER -