Does sleep deprivation make you take more risks?
In this study, yes. After two nights without sleep, healthy adults chose more often from the risky options in a decision-making game, and the older participants were affected most. Thirty-four healthy volunteers played the Iowa Gambling Task once when rested and again after 49.5 hours awake.
Dr. Kumar’s Take
The Iowa Gambling Task is a card game built to mimic real decisions made without full information. Some decks pay big but lose more over time; others pay less but come out ahead. Rested people learn to steer toward the safer decks as the game goes on. After two nights of sleep loss, these volunteers drifted the other way, toward the risky decks, a pattern the authors compare to (though milder than) what is seen in patients with damage to the ventromedial prefrontal cortex. The practical lesson is simple: a long stretch without sleep is a poor time to make a decision that involves weighing risk.
Key Findings
- At rested baseline, volunteers performed like most healthy samples, learning to avoid the high-risk decks and choosing more from the advantageous low-risk decks as the game went on.
- After 49.5 hours of sleep deprivation, they tended to choose more from the risky decks as the game progressed.
- The pattern resembled, in milder form, that seen in people with lesions of the ventromedial prefrontal cortex.
- Age mattered only after sleep loss. When rested, risky choices were unrelated to age. When sleep deprived, older participants made more risky choices.
Study Design
This was a within-person comparison in 34 healthy volunteers, published in the Journal of Sleep Research in 2006 by Killgore, Balkin and Wesensten. Each person completed the Iowa Gambling Task at a rested baseline and again after 49.5 hours of continuous wakefulness. The authors started from the observation that sleep deprivation lowers metabolism in the prefrontal cortex, the brain region most responsible for judgment and decision making.
Why This Matters
Many consequential choices about money, driving, or work are made under uncertainty, which is what this task was designed to mimic. The authors conclude that decision making under uncertainty, a function of the ventromedial prefrontal cortex, may be particularly vulnerable to sleep loss, and that this vulnerability may grow with age.
Limitations To Keep In Mind
This was a small laboratory study using a card task, not real-world decisions. The sleep loss was extreme, about two full nights, so the results do not tell you how a single short night affects judgment. There was no separate rested control group; each person was compared with their own baseline.
FAQs
What is the Iowa Gambling Task?
A card game in which players pick from four decks. Two decks give large rewards but larger losses over time; two give smaller rewards but a net gain. Healthy rested players gradually learn to favor the safer decks.
Does age change the effect of sleep loss on decisions?
In this study, age was unrelated to risky choices when participants were rested, but after sleep deprivation older participants made more risky choices.
Related Studies And Internal Links
- Sleep Restriction Impairs Cognitive Function: Meta-Analysis of 147 Studies
- Sleep’s Role in Emotional Brain Function: Mood Stability
- Overnight Therapy: How REM Sleep May Soften Painful Emotional Memories
- How to Sleep Better: Science Daily Playbook
