2012 June 23 Saturday
Brain Circuits Model Values Of Others

We've got neural circuits in the prefrontal cortex of our brains that model how the values of others differ from our own.

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 that the two signals, each located in distinct prefrontal circuits, strike a balance between expected and observed rewards and choices, enabling humans to predict the actions of people with different values than their own.

What I wonder: If the techniques these researchers developed were applied to the study of autistic test subjects what would be found? Do higher functioning autistics do well or poorly (as compared to neurotypicals) simulating the value systems of others? More generally: do autistics broad deficiencies in their ability simulate the minds of others? Or do they have only specific deficiencies in their capabilities to simulate certain aspects of other minds while being quite strong in other areas? Do they even have special strengths in mind simulation? Are they weak at simulating to predict emotional reactions while being strong at simulating, say, values? Also, do the patterns of simulation weaknesses and strengths vary from autistic to autistic? I would expect that to be the case because so many selected for and de novo mutations for autism cause different autistic attributes.

Our minds have mental circuits for simulating the minds of others.

Learning another person's values and mental processes is often assumed to require simulation of the other's mind: using one's own familiar mental processes to simulate unfamiliar processes in the mind of the other. While simple and intuitive, this explanation is hard to prove due to the difficulty in disentangling one's own brain signals from those of the simulated other.

Research scientists Shinsuke Suzuki and Hiroyuki Nakahara, a Principal Investigator of the Laboratory for Integrated Theoretical Neuroscience at RIKEN BSI, together with their collaborators, set out to disentangle these signals using functional Magnetic Resonance Imaging (fMRI) on humans. First, they studied the behavior of subjects as they played a game by making predictions about the other's behavior based on the knowledge of others and their decisions. Then they generated a computer model of the simulation process to examine the brain signals underlying the prediction of the other's behavior.

Parts of the simulation of values of others take place in the ventromedial prefrontal cortex and the dorsomedial prefrontal cortex.

The authors found that humans simulate the decisions of other people using two brain signals encoded in the prefrontal cortex, an area responsible for higher cognition (Figure 1). One signal involves the estimated value of the reward to the other person, and is called the reward signal, referring to the difference between the other's values, simulated in one's mind, and the reward benefit that the other actually received. The other signal is called the action signal, relating to the other's expected action predicted by the simulation process in one's mind, and what the other person actually did, which may or may not be different. They found that the reward signal is processed in a part of the brain called the ventromedial prefrontal cortex. The action signal, on the other hand, was found in a separate brain area called the dorsomedial prefrontal cortex.

What I also wonder: when faced with large value differences are some people more inclined to feel stressed or hostile than others? Is this due to innate differences caused by genetic variants?

By Randall Parker    2012 June 23 10:51 PM   Entry Permalink | Comments (0)
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