Brain activity tracks the preferences of others.

A new study published by Izuma and Adolphs in Neuron asks what are the brain areas that undergo changes in activity when we modify our preferences to fit social context1. Imagine I show some people a shirt and ask them whether they like it or not. In some cases I tell people that this is the favorite shirt of a certain group of University students. In other cases I tell them that it is the preferred shirt of most criminals. What we get is a socially-manipulated preference – people tend to dislike the criminal’s favorite.

T-Shirt

Ask people what they think of this T-shirt. Then tell another group that this is the favorite T-shirt of all criminals. Now ask this other group what they think – people knowing that criminals like the shirt will rate it lower.

Illustration from MpegMan, released under the GNU license.

The authors looked at brain activities with the following hypothesis in mind: perhaps some brain area would have activities related to cognitive imbalance, that is how far your own preferences are from the normal people or how close they are to the criminal’s preferences. They used a fMRI brain scanner to identify the brain areas that were showing signals related to such cognitive imbalance. They found that activities in the dorsomedial prefrontal cortex was strongly correlated to cognitive imbalance – the area was more or less activated depending on whether or not subjects already had preferences that were different from the criminals or whether their preferences happened to be close to the criminal’s preferences.

The prefrontal cortex had already been targeted in other studies looking at social influence on decisions2. This study confirms the important role of this area in tracking the preferences of others and potentially adjusting our own behavior to social context.

References

1. Izuma K, Adolphs R. (2013) Social manipulation of preference in the human brain. Neuron 78:563-573.

2. Behrens TE, Hunt LT, Woolrich MW, Rushworth MF. (2008) Associative learning of social value. Nature 456:245-249.

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