As anyone who has ever been roped into carrying groceries for his mom will say, sometimes guilt can be a factor in deciding to cooperate. According to a new UA study, this might just be the case.

The study, performed by a team of UA researchers, shows that it could be due to a failure to appropriately cooperate with others.

The researchers, including a neuroscientist, a psychologist and a behavioral economist, used a functional magnetic resonance imaging machine to examine what happens to the brain when humans experience guilt. They did so by devising an economic game in which participants were divided into two groups, “”investors”” and “”trustees.”” Investors were asked to award a certain amount of mone to the trustees, who were told that the investors expected a certain amount of money back. The trustees’ brains were then scanned as they decided how much money to return to the investors.

When the trustees decided to give back the full amount of money, the scans showed significant activity in regions of the brain that are said to be involved in guilt-motivated behavior. When participants did not decide to give back the full amount, different areas of the brain said to be involved in maximizing rewards showed activity.

“”This study shows that this area of the brain that processes negative emotions align at the thought of not cooperating,”” said Luke Chang, lead author of the study and a UA psychology doctoral student.

Chang explained that guilt is a factor in business decisions, business partnerships and to avoid feeling badly about one’s self in the future.

“”You want to make sure you hold up your end of the bargain,”” he said.

The study took two years to be fully performed and analyzed. Chang was initially interested in moral decision-making, so he collaborated with an economics professor to create mathematical models that helped study guilt.

Another point that the study found is that some people are more sensitive to guilt than others. This was demonstrated by testing both the trustees that decided to return the full amount and the trustees who did not separately. When those that decided to not return the full amount imagined returning even less money, their brains still did not show a lot of activity in the neural structure underlying guilt.

Alexander Hishaw, an assistant professor of neurology at the UA, said that some individuals have more guilt-prone personalities than others. This is helpful in having a civilization thrive, he explained, because it would be hard to interact with others if there was no issue of guilt.

“”People would always try and be the alpha male,”” he said. “”For civilizations to exist, there has to be something that allows for some concern or thought as to how our actions impact others around us. Guilt is probably a part of that process.””

Lastly, the study showed that feelings are vital in economic decision-making. Typical decisions are made with more emotions than we might give credit for, and feeling guilty allows us to make more decisions then we realize, according to Hishaw.

Alec Smith, a co-author in the study and a UA economics alumnus, said that the researchers were interested in looking to see how the brain may implement components of the guilt theory in order to make decisions.  

“”It’s interesting to think the kind of work were doing is showing that emotions are real, physical things that matter in decision-making,”” he said.