Gender differences in sleep deprivation effects on risk and inequality aversion: Evidence from an economic experiment

In the modern 24-h society working excessive hours also during the night is becoming increasingly common. The prefrontal cortex (PFC) is particularly vulnerable to the effects of sleep loss and, consequently, the specific behaviors subserved by the functional integrity of the PFC, such as risk-taking, are negatively affected. In this study, we assessed the effects of one night of sleep deprivation on risk and inequality aversion. Since gender differences in risk propensity have already been reported, men and women performance was also compared. Thirty-two university students (16 females) participated to two counterbalanced laboratory sessions in which they performed (incentivized) Risk aversion and Inequality aversion elicitation tasks under two conditions: after one night of undisturbed sleep at home and after one night of sleep deprivation in the laboratory. Sleep deprivation caused increased sleepiness and decreased alertness in all subjects. After sleep loss males made more risky choices compared to the rested condition, while females did the opposite. Females also showed decreased aversion to inequity after sleep deprivation, while men did not. As for the relationship between cognitive ability and economic decisions, we observed that sleep deprived individuals with higher cognitive reflection abilities seem to be more likely to choose riskier lotteries and to show a more altruistic behavior, with respect to subjects with lower cognitive reflection. These results show that after one night of sleep deprivation the economic behaviors are affected in a gender-sensitive way. Gender reactivity to sleep loss was different, suggesting a higher susceptibility of males to the negative effects of sleep deprivation, when they take decisions that involve both risk and distributional concerns. Females' "wiser" reaction to sleep deprivation, characterized by reduced risky choices and increased egoism, may be related to intrinsic psychological gender differences, such as those in the way men and women weight probabilities in their decisions, and/or to the different neurofunctional substrate of decision making.