Is Generosity the Key to Reducing Stress?
Anyone who has bid on something through eBay knows the small tug of war that happens in your head. Bid too high and you might end up paying more than you wanted. Bid too low and someone else walks off with the shoes you had your heart set on. Do this enough times and it starts to wear on you mentally. What most people never notice is that the back-and-forth leaves a physical mark too, loading your body with stress as it happens.
A team at Queensland University of Technology (QUT) set out to track exactly that. They watched the bodily responses of people playing a financial bargaining game and found two things. People handed a stingy offer felt the strain, which you might expect. Less obvious: people who made generous offers reported better emotional wellbeing. The work appeared in the journal Public Library of Science (PLOS) ONE, and it looked at the emotional side of decisions in ultimatum settings, a subject that usually gets studied through interviews or surveys rather than physical measurement.
The game at the center of it is the Ultimatum Bargaining Game, or UBG. Two players split a fixed pot of money. One of them, the proposer, decides how the money should be divided. The other, the responder, either takes the split or turns it down. If the responder says no, both walk away with nothing. That simple structure has made the UBG one of the most studied setups in experimental economics, and it maps onto how social preferences and raw emotion shape the choices people make. We face ultimatum-style decisions constantly, so a game like this gives researchers a usable stand-in for everyday behavior.
Earlier studies built around the UBG leaned on brain-scanning equipment to read what was going on inside participants, which kept the research tethered to the lab. This group took a lighter approach and measured heart rate variability (HRV) instead, the small differences in the time between one heartbeat and the next. According to Uwe Dulleck, a professor with QUT's Queensland Behavioural Economics Group (QuBE), this was among the first economics experiments to use HRV as a window into mental stress during decision-making.
"We wanted to understand the physiological reactions people have in these situations, so responders and proposers wore heart rate monitors to track Heart Rate Variability (HRV), the variation in the time interval between heart beats," Dulleck said. He described HRV as something that registers a kind of cardiac signature, a theater of the emotions, with both theoretical and experimental backing. What the readings showed was striking. Low offers, usually anything under 40 percent of the pot, pushed up HRV activity and stress in both players, not only the one receiving the bad deal.
Co-author Dr. Markus Schaffner, who manages QuBE's Laboratory for Economic Experiments at QUT, offered guilt as one likely reason the proposer's stress climbed. "This can be seen as evidence that we empathise with people and put ourselves in their shoes in these sorts of situations," he said. He added that the data point to real discomfort when we shortchange someone: "The results indicate we have negative feelings when we treat someone unfairly, for example by offering below 40 per cent of the total in the game. There is an emotional and physiological cost and we feel uncomfortable."
On the responder's side, Schaffner pointed to two sources of the arousal that the HRV numbers captured. "First, because they have suffered from unfairness, and second, because they have an opportunity to punish the proposer by rejecting the offer and leaving them both without any money." He framed the flip side plainly: fairness is what we lean toward, and proposers probably get a small jolt of satisfaction from offering a fair split.
One question the study could not settle is which way the arrow runs. As Dulleck put it, "Do emotions dictate behaviour or does behaviour induce emotional response? Our results can give no definite answer to this question, but do clearly indicate a link between emotional state and the decision."
So the next time you go to place a bid, trust your gut and put in an offer that feels fair and honest. The evidence suggests generous behavior tracks with better wellbeing, while self-serving behavior tends to come paired with more stress.