Selling out: why some beliefs are not worth keeping

A new study of the brain has found what makes us decide to sell principles for profit

Whether you're a political pundit, a serious musician or a football club diehard, "selling out" is regarded as the lowest of acts.

But the decision to trade our principles for profit appears to be made at a deeper level than we realise.

A new study by American researchers into the neuroscience of selling out has found that the brain uses different processes to differentiate between personal values we hold sacred – whether a religious belief, a national identity or a code of ethics – and those we are prepared to disavow for a price.

"What we're seeing in the brain is that there are distinct neural systems for processing things we think of as sacred, versus those we think of as more mundane," says Gregory Berns, the director of the Centre for Neuropolicy at Atlanta's Emory University, and lead author of the study.

The researchers used functional magnetic resonance imaging to record the brain responses of 32 adults throughout their experiment. Participants were presented with 62 statements, ranging from the mundane ("You are a tea drinker") to the contentious ("You support gay marriage" or "You are pro-life"), then asked to indicate whether the statement or its opposite held for them.

Participants were then given the option of auctioning their personal statements, disavowing their previous choices for cash. They could earn as much as $100 per statement by agreeing to sign a document saying the opposite of what they believed, or opt out of the auction for statements that they valued highly.

The study found that "sacred" values – those the participants would not sign away for cash – prompted greater activation of the part of the brain associated with evaluating rules-based, right-or-wrong thought processes: the same neural systems used for processing rules of grammar, syntax or street signs. The statements that were disavowed prompted greater activity in the parts of the brain associated with reward-based systems.

The findings suggested that public policy which sought to use incentives to alter people's positions on "sacred" issues were likely to be unsuccessful.

"Almost all policy – economic, foreign or military – is based entirely on incentive or disincentive," he said. That was appropriate in many circumstances, except when it came to the "realm of the sacred, because the biology suggests that these are completely different types of decision-making processes.

"It may not be possible for people to apply a cost-benefit decision-making system to things like religion or ethnicity or national identity."