Sleep Deprivation Adversely Affects Perceptual, But Not Quantitative, Capabilities



For a perceptual ability task, performance is sensitive to sleep deprivation and decreases throughout the night. However, subjects’ self-assessment does not decrease, leading to an inability to accurately gauge their performance.

SEATTLE—Sleep deprivation impairs perceptual, but not quantitative, abilities, according to research presented at the 23rd Annual Meeting of the Associated Professional Sleep Societies. In addition, people with sleep deprivation are less able to predict how they will perform on perceptual ability tasks.

Jennifer M. Steward, a student at the University of North Texas in Denton, and colleagues assessed the relationship between actual and self-assessed performance on quantitative and perceptual tasks in sleep-deprived persons during an internship at Clemson University in South Carolina. This research was part of a larger investigation led by June J. Pilcher, PhD, a Professor in the Department of Psychology at Clemson University. The level of confidence that subjects displayed was also assessed.

Twenty-three participants (15 males; mean age, 21.1) completed the Graduate Record Examinations (GRE) Quantitative task (ie, algebra equations) and the perceptual ability subtests (ie, matching 3-D figures to 2-D representations) of the Dental Admissions Test (DAT) while being sleep deprived for one night. The study was conducted between 9:30 am on day 1 and 1:30 pm on day 2, and participants completed each task four separate times (6:30 pm to 10:30 pm, 11:00 pm to 3:00 am, 3:30 am to 7:30 am, and 8:00 am to 12:00 pm).

Subjects then completed a meta-cognitive survey assessing their performance and the confidence they felt after completion. Ms. Steward’s group compared actual and estimated performances and measured the confidence levels that participants had with each task.

Sleep loss did not have a significant effect on the participants’ performance on the quantitative task. No substantial change was observed among the four sessions in either actual or estimated performance. However, subjects who were sleep-deprived had overestimated their performances.

In contrast, the perceptual ability tasks were continually and adversely affected by sleep loss, although no significant change was seen in estimated performance. “This [difference] could be due to the engaging/interesting tasks being able to hold one’s attention better than long or monotonous tasks,” the researchers theorized. A significant difference was found between actual and estimated performance among perceptual ability tasks.

“Throughout the night and for the different tasks, participants consistently reported high levels of confidence in their assessments of their performance, and that confidence level did not waiver throughout the night of sleep deprivation,” Ms. Steward and colleagues reported. “These results can be related to performance on tasks in the work force and within the realm of education. A full night of sleep can often be hard to come by; therefore, it is important to understand the effects of sleep loss on performance and our own perceptions of performance.”

—Laura Sassano

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