Brain activity reveals how well we mentally size up others

(Press-News.org) How quickly do we perceive whether a person we are interacting with is clever or predictable? Be it in a game, a conversation or a negotiation, we constantly infer what others are thinking and size up their intentions, and we adjust our behavior accordingly in a process that scientists call “adaptive mentalization.” A new study by the University of Zurich now reveals how our brains govern this adaptation.

Differences in social mentalization

A team of researchers led by Christian Ruff, a professor of neuroeconomics and decision neuroscience at the University of Zurich, examined the behavior of over 570 people in different game situations. The study subjects played a repeated rock-paper-scissors game against human or artificial opponents. With the aid of a novel computational model, the researchers quantified how strategically the subjects sized up their respective opponents and how much they adapted their estimation of them after each round. The study found that most of the subjects reacted flexibly when the opponent’s behavior changed, but there was a wide range of reaction flexibility between the participants in the study. “Some can do that very quickly – they are often good at recognizing what strategy their opponents are employing. Others take much longer to correctly infer their opponent’s behavior,” Christian Ruff observes.

Social brain network becomes active

Using functional magnetic resonance imaging, the researchers were able to identify a distributed network encompassing several regions of the brain that shows increased activity whenever subjects rethink their estimation of their opponent. The temporoparietal cortex, which plays a vital role in contemplating the thoughts and intentions of others, is particularly important here, as is the dorsomedial prefrontal cortex, which is involved in appraising social information. The anterior insula and adjacent areas of the ventrolateral prefrontal cortex also exhibit a spike in activity, particularly when expectations turn out wrong and a reassessment becomes necessary. “In these moments, activity in those areas of the brain measurably changes,” explains Gökhan Aydogan, a postdoctoral researcher at the University of Zurich’s Department of Economics.

Social adaptation becomes predictable

What matters is that these activity patterns make it possible to predict how much a person adapts their estimation. “This prediction worked even with subjects whose brain data had not yet been added to the model,” Ruff says. The researchers thus speak of a neural fingerprint of adaptive mentalization. Prediction was successful with almost 90% of the study participants.
 

Previous research had examined social cognition mostly through static tasks such as short stories or single decisions. The new study, in contrast, utilized dynamic interactions that are more similar to those in everyday life. The study shows that mentalization is not a static state, but rather an ongoing adaptation process. “Our findings may help to apprehend social cognition abilities more objectively in the future,” Ruff says. This is particularly pertinent for neurological disorders such as autism or borderline personality disorder that hamper social interactions. “Neural markers of this kind may also help in the long run to evaluate and further develop therapies in a more targeted manner,” Ruff adds.

Literature

Niklas Buergi, Gökhan Aydogan, Arkady Konovalov, Christian C. Ruff. A neural fingerprint of adaptive mentalization. Nature Neuroscience. 9 March 2026. Doi: 10.1038/s41593-026-02219-x

Contact

Christian Ruff

Professor of Neuroeconomics and Decision Neuroscience

University of Zurich

Phone +41 44 634 50 67

E-mail: christian.ruff@econ.uzh.ch

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