Circadian photoreception influences loss aversion.

Gambling behaviour is a persistent and growing societal problem. An unexplored factor that may encourage gambling behaviour is the impact of circadian photoreception on cognitive processes underlying the behaviour. We investigated the influence of circadian photoreception on loss aversion in gambling by altering the blue content of light while maintaining the same visual brightness. Fifteen participants (age 18-27 years, M = 20.40, SD = 2.03) completed an economic decision-making task under blue-enriched and blue-depleted light, of equivalent visual brightness, on separate occasions in a randomised order. The task required participants to choose between taking a risky gamble of a positive and negative outcome, or a less risky guaranteed outcome. Hierarchical Bayesian Modelling was conducted to derive individual parameter estimates for loss aversion, and trial-by-trial performance was analysed using linear mixed models. The findings demonstrated that individuals were significantly less loss averse under blue-enriched light compared to blue-depleted light (β = - .43, 95% CI [- .82, - .04], p = .03). This study shows that exposure to light that preferentially targets circadian photoreception reduces loss aversion, which may encourage gambling behaviour.