People make more moral decisions when they think their heart is racing

Why did the proverbial Good Samaritan cross the road to help the injured stranger? Perhaps he listened to his heart. Not in the poetic sense, but literally. A new study by Jun Gu and his colleagues has highlighted the way cardiac feedback influences people's moral decisions. When students were fed false feedback, leading them to think their heart was racing, they were more likely to volunteer for a good cause and less likely to lie to gain more money.

Eighty-six undergrads arrived at a psychology lab and were asked if they could quickly test out some heart-recording equipment that was needed for a separate study. A wrist monitor was attached to a headset though which false normal (60 beats per minute) or fast (96 beats per minute) heartbeat sounds were played. While the students test-drove the equipment, they were asked to read a recruitment letter, seeking their time for another study into the negative consequences of homophobic discrimination. Forty per cent of students who heard their heart beating fast agreed to volunteer their time, as compared with 17 per cent of students who heard their heart beating at a normal speed.

A second study with 65 more students was similar, but this time as the students tested the heart-monitoring equipment, they played a quick money-sharing game. They simply had to decide whether to instruct their partner, located in another room, to pick option A (which was actually more lucrative for the participant him or herself) or option B (more lucrative for the partner). Participants who heard their heart beating fast were less likely to lie and tell their partner that he or she would be better off choosing option A (31 per cent of them did so, compared with 58 per cent of participants who heard their heart beat at normal speed). A handful of participants were suspicious about the false heart feedback so they were excluded from the analysis, though the general pattern of results was the same with their data included or omitted.

Gu and his colleagues think that a fast heart beat is interpreted by people as a sign they are stressed and that they should adhere to moral conventions as a way to escape that stress. The new finding is consistent with Antonio Damasio's influential Somatic Marker hypothesis, which is based on the idea that bodily feedback guides our decisions, often at a non-conscious level. For example, people playing a card game sweat more when picking from the wrong, costly pile, even before they've realised at a conscious level that it's the wrong choice. The new research also complements recent research showing how bodily perceptions can influence the moral conscience. In one study, participants were less likely to volunteer their time after being given the chance to wash their hands – as if the process of physical cleansing left them feeling less need to compensate for past transgressions.

Cardiac feedback doesn't affect everyone in the same way. In further experiments, Gu and his colleagues demonstrated that the moral decision-making of people who are more mindful (for example, they agreed with statements like: "I perceive my feelings and emotions without having to react to them") was unaffected by the false cardiac feedback. The researchers also found that telling participants that the financial game was a "decision-making" task led to immunity from the false heart feedback, relative to being told the game was an "intuitive task".

This last result is particularly intriguing since we usually assume that thinking more deliberatively helps rein in the wild horses of our emotions, allowing us to behave more morally. The finding of Gu's team suggests that in some circumstances at least, thinking more deliberately can undermine the influence of the heart, actually making it less likely that we'll make a more moral decision.

"The current research reveals that perceived physiological experiences play an important role in influencing moral behaviours," the researchers said. "Listening to your heart may indeed shape ethical behaviours."

Further reading

Gu J, Zhong CB, and Page-Gould E (2012). Listen to Your Heart: When False Somatic Feedback Shapes Moral Behavior. Journal of experimental psychology. General PMID: 22889162