Heart beats and economic decisions : Observing mental stress in the ultimatum bargaining game

One aim of experimental economics is to try to better understand human economic decision making. Early research of the ultimatum bargaining game (Gueth et al., 1982) revealed that other motives than pure monetary reward play a role. Neuroeconomic research has introduced the recording of physiological observations as signals of emotional responses. In this study, we apply heart rate variability (HRV) measuring technology to explore the behaviour and physiological reactions of proposers and responders in the ultimatum bargaining game. Since this technology is small and non-intrusive, we are able to run the experiment in a standard experimental economic setup. We show that low o�ers by a proposer cause signs of mental stress in both the proposer and the responder, as both exhibit high ratios of low to high frequency activity in the HRV spectrum.