To identify neural computations and brain network mechanisms that underlie social behaviour, we conducted several studies with functional magnetic resonance imaging (fMRI) and/or electroencephalography (EEG). These studies focused on different types of social behaviours, such as leadership, trust, altruism, moral decisions, norm compliance, and strategic choice. Together, these studies highlight various shared types of neural computations and functional interactions in the social brain network that underlie distinct aspects of social behaviour. Moreover, they highlight some key areas that appear to implement these computations and interact with one another (among them the temporo-parietal junction, TPJ, and the lateral and medial prefrontal cortex, lPFC and mPFC). In one notable study, we identified a truly multivariate pattern of neural activity across the whole brain network that can predict how flexibly people can adapt to other people’s behavioural strategies. We have established computational models that allow researchers to investigate, for all these types of behaviour, how the information about social context can be integrated with non-social information to control action.
We tested the causal relevance of these identified neural processes by means of brain stimulation studies. Key findings of these studies are that the TPJ is causally relevant for moral decisions and for computations that allow people to incorporate other’s perspectives into their own behaviour, that the lPFC is causally relevant for compliance with social norms, that neural coherence between frontal and parietal areas facilitates altruism.
Finally, to establish the clinical relevance of these processes, we tested various groups of people with impaired brain function due to aging, stroke, Borderline Personality Disorder, Autism Spectrum Disorder, and Post-Traumatic Stress Disorder. Our results show that healthy aging leads to a decrease in the use of the neural computations underlying the ability to take strategic decisions, that Asperger’s syndrome is associated with an inflexibility in adapting to other people’s changing strategies, and that Borderline Personality Disorder is associated with biases and instabilities in the way beliefs about others are adapted in response to information about their behaviour.
The results of all studies have been shared at numerous conferences with scientific audiences and at events for decision makers and the interested public, and have been (or are being submitted to be) published in peer-reviewed journals. Moreover, to summarise the aims and findings of the project, we have outlined our theoretical approach in literature reviews, and we have provided an overview of our methodical approach in review papers that provide the field with clear guidelines for conducting and assessing brain stimulation studies on the neural computations and network mechanisms underlying behaviour.
