Framing effect, probability distortion, and gambling tendency without feedback are resistant to two nights of experimental sleep restriction

Abstract

Several studies suggest that sleep deprivation affects risky decision making. However, most of these are confounded by feedback given after each decision, indicating that decisions may be based on suboptimal feedback-learning rather than risk evaluation. Furthermore, few studies have investigated the effect of sleep loss on aspects of prospect theory, specifically the framing effect and probability distortion. In this within-subjects design, 25 people had (i) two nights of an 8 h sleep opportunity, and (ii) two nights of a 4 h sleep opportunity, in a counter-balanced order. Following the two nights, they performed a gambling task with no immediate feedback; for each round, they could either gamble for a full amount, or take a settlement framed as a gain or a loss for part of the amount. Sleep restriction did not significantly affect the tendency to gamble, the framing effect, or probability distortion, as compared to normal sleep. These results indicate that two nights of sleep restriction affects neither general gambling tendency, nor two of the main predictions of prospect theory. This resilience may be due to a less extreme sleep loss than in previous studies, but also indicates that learning components and risk biases should be separated when assessing the effect of sleep loss on risky behaviour.

Figure 1

Gambling protocol for (a) loss frame and (b) gain frame.

Figure 2

Percentages of trials gambled in the loss frame & gain frame after normal sleep and after sleep restriction to two nights with 4 hours’ time in bed per night. Error bars represent the standard error of the mean (SEM).

Figure 3

The probability distortion in both sleep conditions for loss and gain frames. Error bars represent the standard error of the mean (SEM). Dashed line represents risk-neutral behaviour.

Figure 4

Percentage (%) of trials in which subjects chose the gamble option in the gain and loss frames, for the four different starting amounts for both conditions. Error bars represent the standard error of the mean (SEM). Dashed line represents risk-neutral behaviour.