Intelligence predicts better cognitive performance after normal sleep but larger vulnerability to sleep deprivation.

Fluid intelligence is seen as a beneficial attribute, protecting against stress and ill-health. Whether intelligence provides resilience to the cognitive effects of insufficient sleep was tested in the current pre-registered experimental study. Participants (N = 182) completed the Raven's test (measuring fluid intelligence) and a normal night of sleep or a night of total sleep deprivation. Sleepiness and four cognitive tests were completed at 22:30 hours (baseline), and the following day after sleep manipulation. At baseline, higher fluid intelligence was associated with faster and more accurate arithmetic calculations, and better episodic memory, but not with spatial working memory, simple attention or sleepiness. Those with higher fluid intelligence were more, not less, impacted by sleep deprivation, evident for arithmetic ability, episodic memory and spatial working memory. We need to establish a more nuanced picture of the benefits of intelligence, where intelligence is not related to cognitive advantages in all situations.