Pink Elephants on the Road: Visual Illusions and Distortions when Driving during Significant Sleep Deprivation

Abstract

Visual hallucinations, illusions, and distortions have been observed in individuals undergoing severe periods of extended wakefulness. However, the incidence of these perceptual phenomena occurring during applied domains such as driving have been underreported. This study investigates effects of a 30-hour period of extended wakefulness during which participants abstained from stimulants and were not allowed to sleep or nap. Participants drove every 4 hours during this period on an uneventful 30-minute driving route in a fullcab high fidelity driving simulator. At the end of the study, participants reported whether they experienced significant visual illusions or distortions, and when the events occurred. Participants reported visual distortions and illusions during drives comprising a time period between 22 and 30 hours awake. Furthermore, self-reported mental workload and extroversion predicted the likelihood of experiencing the visual phenomena. Potential mechanisms for this relationship and possible consequences for safe driving performance during significant sleep deprivation are discussed.