Risk Taking for Potential Losses (but Not Gains) Increases with Time of Day

Bedder, Rachel, Matilde M. Vaghi, Raymond J. Dolan, and Robb Rutledge. 2020. “Risk Taking for Potential Losses but Not Gains Increases with Time of Day.” PsyArXiv. December 17. doi:10.31234/osf.io/3qdnx

Abstract: Humans exhibit distinct risk preferences when facing choices involving potential gains and losses. These preferences are subject to neuromodulatory influence, particularly from dopamine and serotonin. As these neuromodulators manifest distinct circadian rhythms, this suggests decision making under risk might be affected by time of day. Here, in a large subject sample (N = 26,899), we tested the hypothesis of a diurnal modulation in risk taking for gains and losses. We found that risky options with potential losses were increasingly chosen over the course of the day, but observed no such change for how often risky options with only potential gains were chosen. Using a computational modelling approach to obtain a more fine-grained account, we show this diurnal change in risk preference reflects a decrease in sensitivity to increasing losses, but no change in the relative impacts of gains and losses on choice. This diurnal sensitivity, present across two different task designs, was robust to between- and within-subject analysis, to country (i.e., UK and US samples), age, and gender. Thus, our findings reveal a striking diurnal modulation in human decision making, a pattern with potential importance for real-life preferences that include voting, medical decision making, and global stock market investments.