Looking without seeing or seeing without looking? Eye movements in sustained inattentional blindness.

Inattentional blindness (IB) describes the failure to notice salient but unexpected stimuli when attention is partially engaged by another task. Few studies have explicitly investigated the role of eye movements in IB and the relative contributions of overt and covert attention. We recorded eye movements in a series of IB experiments using dynamic stimuli. Results indicate that eye movements do not predict IB; noticers and nonnoticers were equally likely to fixate on or near the unexpected item, often for similar durations. Perceptual load also determines whether observers will fixate the unexpected object. In a high perceptual load task, IB was high (81%) and most participants did not allocate overt attention to the unexpected object. Under lower perceptual load IB decreased to 54% and both noticers and nonnoticers fixated on the unexpected object.