Researchers have isolated a specific pathway our brains use when learning new beliefs about others’ motivations, a new study says.
Though this type of learning, like many others, depends heavily on the neurotransmitter chemical dopamine‘s influence in a set of ancient brain structures called the basal ganglia, it’s also influenced by the rostral anterior cingulate cortex (ACC) – a structure that helps us weigh certain emotional reactions against others – indicating that emotions like empathy also play crucial roles.
As we play competitively against other people, our brains get to work constructing mental models that aim to predict our opponents’ future actions. This means we’re not only learning from the consequences of our own actions, but figuring out the reasons behind others‘ actions as well. This ability is known as theory of mind, and it’s thought to be one of the major mental skills that separates the minds of humans – and of our closest primate cousins – from those of other animals.
Though plenty of studies have examined the neural correlates of straightforward cause-and-effect learning, the process by which we learn from the actions of other people still remains somewhat unclear – largely because complex emotions like empathy and regret seem to involve many areas of the brain, including parts of the temporal, parietal and prefrontal cortices, as well as more ancient structures like the basal ganglia and cingulate cortex.
That’s why a team led by the University of Illinois’ Kyle Mathewson set out to track exactly what happens in our brains as we learn new ideas about other’s motivations, the journal Proceedings of the National Academy of Sciences reports.
The team used functional magnetic resonance imaging (fMRI) to study activity deep within volunteers’ brains as they played a competitive betting game against one another – focusing especially on moments when players learned whether they’d won or lost a round, and how much their opponents had wagered.
The researchers then used a computational model to match up patterns of brain activity with patterns of play – and found that the volunteers’ brains learned others’ behaviors and motivations through a complex interplay of several regions:
We found that the reinforcement learning (RL) prediction error was correlated with activity in the ventral striatum.
In other words, the ventral striatum – an area of the basal ganglia – was crucial for learning by reinforcement, much as the researchers expected…
In contrast, activity in the ventral striatum, as well as the rostral anterior cingulate (rACC), was correlated with a previously uncharacterized belief-based prediction error. Furthermore, activity in rACC reflected individual differences in degree of engagement in belief learning.
…while the anterior cingulate, on the other hand, seemed to dictate how attentively players watched their opponents’ patterns of play, and how much thought they put into predicting those patterns.
Thus, it appears that theory of mind is built atop an ancient “substructure” of simple reinforcement learning, which supports layers of more emotionally complex attitudes and beliefs about others’ thoughts, feelings and motivations – many of which are influenced by our perceptions of our own internal feelings.
And that points back to an important aspect of subjective experience in general: Many of our perceptions of the external world are extrapolated from our perceptions of our internal states. When we say, “It’s hot,” we really mean, “I feel hot;” when we say, “It’s loud in here,” we really mean, “It sounds loud to me.” In fact, the great philosopher Bertrand Russell has gone so far as to suggest that instead of saying, “I think,” it’d be more accurate to say “It thinks in me,” the same way we say “It’s raining.”
Anyway, no matter how you choose to phrase it, the point is that thinking isn’t a single process, but a relationship of many processes to one another. Which means that no matter how much we think we know, there’s always plenty left to learn.