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 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.