Under High Perceptual Load, Observers Look but Do Not See

High perceptual load reduces distractor processing and increases inattentional blindness for unexpected stimuli. We reported previously that high perceptual load reduces memory accuracy and impairs eyewitness identification. Here, we used eye tracking to investigate whether memory impairments under load are due to inattentional blindness or a failure to visually inspect stimuli. Seventy-two participants viewed high or low load versions of a video depicting a theft and identified characters in the video from photographic line-ups. High perceptual load impaired participants' ability to identify the peripheral character (witness) but not the central character (thief). There was no effect of perceptual load on number of ocular fixations on the witness, time to first fixation or total visit duration. We conclude that memory impairments under load are due to attentional failures rather than differences in visual search behaviour. These findings suggest that high perceptual load scenes may hamper eyewitnesses' ability to encode easily visible stimuli. Copyright (c) 2017 John Wiley & Sons, Ltd.