Scientists have found that a person’s honest behaviour can be increased using non-invasive electrical brain stimulation.In a die-rolling experiment, study participants could increase their earnings by cheating rather than telling the truth.
The researchers found that people cheated a significant amount of the time. However, many participants also stuck to the truth.
“Most people seem to weigh motives of self-interest against honesty on a case-by-case basis; they cheat a little but not on every possible occasion,” said Michel Marechal, professor at the University of Zurich (UZH) in Switzerland. However, about 8% of the participants cheated whenever possible and maximised their profit.
The researchers applied transcranial direct current stimulation over a region in the right dorsolateral prefrontal cortex (rDLPFC). This non-invasive brain stimulation method makes brain cells more sensitive – they are more likely to be active.
When the researchers applied this stimulation during the task, participants were less likely to cheat. However, the number of consistent cheaters remained the same.
“This finding suggests that the stimulation mainly reduced cheating in participants who actually experienced a moral conflict, but did not influence the decision making process in those not in those who were committed to maximising their earning,” said Christian Ruff, Professor at UZH.
The researchers found that the stimulation only affected the process of weighing up material versus moral motives.They found no effects for other types of conflict that do not involve moral concerns (such as financial decisions involving risk, ambiguity, and delayed rewards).
Similarly, an additional experiment showed that the stimulation did not affect honest behaviour when cheating led to a payoff for another person instead of oneself and the conflict was therefore between two moral motives.
The pattern of results suggests that the stimulated neurobiological process specifically resolves trade-offs between material self-interest and honesty.
According to the researchers, these findings are an important first step in identifying the brain processes that allow people to behave honestly. “These brain processes could lie at the heart of individual differences and possibly pathologies of honest behaviour,” said Ruff.
The new results raise the question as to what degree is honest behaviour based on biological predispositions, which may be crucial for jurisdiction.
“If breaches of honesty indeed represent an organic condition, our results question to what extent people can be made fully liable for their wrongdoings,” said Marechal.