Looking at human eyes affects contralesional stimulus processing after right hemispheric stroke

Human eyes are a powerful social cue that may automatically attract the attention of an observer. Here we tested whether looking towards open human eyes, as often arises in standard clinical “confrontation” tests, may affect contralesional errors in a group of right brain-damaged patients showing visual extinction. Patients were requested to discriminate peripheral shape-targets presented on the left, right or bilaterally. On each trial they also saw a central task-irrelevant stimulus, comprising an image of the eye-sector of a human face, with those seen eyes open or closed. The conditions with central eye stimuli open (versus closed) induced more errors for contralesional peripheral targets, particularly for bilateral trials. These results suggest that seeing open eyes in central vision may attract attentional resources there, reducing attention to the periphery, particularly for the affected contralesional side. The seen gaze of the examiner may thus need to be considered during confrontation testing, and may contribute to the effectiveness of that clinical procedure.