The brain recruits its own decision-making circuits to simulate how other people make decisions

The researchers scanned participants' brains while they made a simple decision and while they predicted other people's decisions about the same task. Credit: 2012 Hiroyuki Nakahara, RIKEN Brain Science Institute

A team of researchers led by Hiroyuki Nakahara and Shinsuke Suzuki of the RIKEN Brain Science Institute has identified a set of brain structures that are critical for predicting how other people make decisions.

This phenomenon is thought to involve simulation learning, a process by which the brain generates a model of how another person will act by directly recruiting its own decision-making circuits. However, little else is known about the underlying brain mechanisms.

Nakahara and his colleagues used to scan participants' brains while they performed two simple decision-making tasks. In one, they were shown pairs of and had to choose the 'correct' one from each, based on randomly assigned reward values. In the second, they had to predict other people's decisions for the same task.

The researchers confirmed that the participants' own decision-making circuits were recruited to predict others' decisions. The scans showed that their brains simultaneously tracked how other people behaved when presented with each pair of stimuli, and the rewards they received.

Effective simulated learning occurs when the brain minimizes two different prediction errors—the discrepancies between its prediction of others' actions and the rewards they received and how they actually acted and were rewarded. The researchers found that each of these variables was associated with activity in a distinct part of the prefrontal cortex (PFC).

The bigger the prediction error in simulating other people's rewards, the more activity was observed in the (vmPFC) an area located at the base of the frontal lobe of the brain that is associated with decision making, while the larger the prediction error in simulating another's actions, the more active were the dorsomedial and dorsolateral prefrontal cortices.

The ability to attribute to others is referred to as , or 'mentalizing', and is widely thought to involve the PFC. This, however, is the first study to show that activity in the PFC encodes prediction errors of one's own rewards as well as those of the simulated decisions of other people, and that both of these signals are required for simulated learning. "We showed that simple simulation is not enough [to predict other peoples' decisions], and that the simulated other's action is used to track variations in another person's behavior," says Nakahara. "In real life, some people are similar to us but others are not. Yet, we still interact with different types of people somehow, and next we hope to understand how this is possible."

More information: Suzuki, S., Harasawa, N., Ueno, K., Gardner, J.L., Ichinohe, N., Haruno, M., Cheng, K. & Nakahara, H. Learning to simulate others' decisions. Neuron 74, 1125–1137 (2012). www.cell.com/neuron/abstract/S… -6273%2812%2900427-8

add to favorites email to friend print save as pdf

Related Stories

How humans predict other's decisions

Jun 20, 2012

Researchers at the RIKEN Brain Science Institute (BSI) in Japan have uncovered two brain signals in the human prefrontal cortex involved in how humans predict the decisions of other people. Their results suggest ...

Neural balls and strikes: Where categories live in the brain

Jan 15, 2012

Hundreds of times during a baseball game, the home plate umpire must instantaneously categorize a fast-moving pitch as a ball or a strike. In new research from the University of Chicago, scientists have pinpointed an area ...

Brain activity encodes reward magnitude and delay during choice

Jul 09, 2008

Good things may come to those who wait, but research has proven that humans and animals actually prefer an immediate rather than a delayed reward. Now, a study published by Cell Press in the July 10 issue of the journal Neuron reveal ...

Recommended for you

Damage to brain networks affects stroke recovery

Nov 21, 2014

(Medical Xpress)—Initial results of an innovative study may significantly change how some patients are evaluated after a stroke, according to researchers at Washington University School of Medicine in St. ...

Dopamine leaves its mark in brain scans

Nov 21, 2014

Researchers use functional magnetic resonance imaging (fMRI) to identify which areas of the brain are active during specific tasks. The method reveals areas of the brain, in which energy use and hence oxygen ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.