What makes you change your mind?

When we face opinions that differ from our own in everyday life, we either maintain our stance or we change our mind. But how do we decide? One thing is for sure, unless we are very confident in our opinion, our decision will most likely be influenced by others.

Scientists supported by the EU-funded rid-O project have now given us greater insight into how brain activity makes a distinction between different types of social influence when we change our mind. Their study was published in the journal ‘PLOS Biology’.

Social influence can be considered either informational or normative. Changing our opinions based on our desire to be right, because we believe that the other person has more accurate information, is an example of informational social influence. However, when we change our mind for reasons unrelated to accuracy – in order to fit in with a group or because we do not want to be left out – this is called normative social influence. This study takes a look at how the brain differentiates between informational and normative factors when we are socially influenced to change our mind.In the study, participants were asked to observe a series of dots that appeared on the screen. They then had to say where on the screen the very first dot appeared and report how confident they were about their answer on a scale of 1 to 6. Participants were then shown the estimate made by a partner they were paired with. While participants were told that in two of the four blocks of trials their partner was a computer, in reality, all estimates were computer-generated. In half the trials, participants were given the chance to revise their estimates; in the other half, the partner did and participants were then shown the partner’s revised estimate. Participants’ brain activity as they performed the task was measured using functional magnetic resonance imaging.

The results were quite revealing. Participants changed their minds based on informational social influence – that is, their confidence in their opinion – whether they believed their partner was a computer or human. However, a change of mind for reasons related to normative conformity was only observed in what they believed were interactions with other humans. “Human dorsal anterior cingulate cortex tracks the weight of others’ opinion in social interaction. This brain signal treats advice from humans and from artificial intelligence similarly in matters of information. In matters of social norms such as reciprocity, however, this brain area gives no weight to AI,” explained lead author Dr Ali Mahmoodi of the University of Freiburg, Germany, in a news item posted on ‘Neuroscience News’.

“When humans interact with an inanimate computer partner, this form of normative conformity is not observed neither in behaviour nor in the human brain,” observe the authors in the study partly supported by rid-O (Improving collective decisions by eliminating overconfidence: mental, neural and social processes). “This will have important ramifications for the new and burgeoning field of human–AI interactions. For example, with the imminent introduction of self-driving cars into everyday life, studies such as ours will be able to help anticipate the emergence of norms of politeness between human and AI drivers on the road.”

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rid-O project