Decision-Making under Stress: The Hiding behind a Small Cake Effect

Objective: we analyzed decision-making under stress by manipulating salivary cortisol levels. Theoretical background: literature dedicated to the relationship between stress and decision-making is still inconclusive. Studies have found that when dealing with stressful decisions, people will respond with a greater propensity for opportunistic behavior. However, stress might also decrease the potential for deception when the decision requires strategic/analytical responses. Method: we implemented a laboratory experiment using the ultimatum game with asymmetric information, in which only the first mover was fully informed about the size of the endowment. Our experiment compared the decisions of subjects who received a stress stimulus from an adapted Trier social stress test for groups (TSST-G) protocol with a control group. Results: we found that under stress, proposers transferred more to responders. In contrast, non-stressed players were more likely to take advantage of information asymmetry by choosing lower strategic offers, which is consistent with the so-called ‘hide behind a small cake’ effect. Regression analysis also indicated that larger offers are not necessarily associated with increased prosocial motives since stressed proposers became more confident about the responder’s ability to guess the true endowment, which decreased their incentive to take advantage of the aforementioned effect. Conclusions: one possible effect of stress could be an increase in risk perception, decreasing the ability to make strategic decisions. The stressful condition might have rendered our participants less capable of realizing the ‘hide behind a small cake’ potential of the game, leading them to make more conservative offers when compared to the control group.