Brain Activity Reveals How Well We Mentally Size Up Others

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.

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 550 people in different game situations. The study participants played a repeated rock-paper-scissors game against human or artificial opponents. With the aid of a novel computational model that formalizes the underlying thought processes, the researchers quantified how strategically the participants      sized up their respective opponents and how much they adapted their estimation of them after each round. The study found that most of the participantsvreacted 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,” says Niklas Bürgi, co-first author of the study, formerly at the University of Zurich and now at the Max Planck Institute for Biological Cybernetics.

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 participants 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.

What matters is that these activity patterns make it possible to predict how much a person adapts their estimation. “This prediction worked even with participants 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