A dual-fMRI investigation of the iterated Ultimatum Game reveals that reciprocal behaviour is associated with neural alignment

Abstract

Dyadic interactions often involve a dynamic process of mutual reciprocity; to steer a series of exchanges towards a desired outcome, both interactants must adapt their own behaviour according to that of their interaction partner. Understanding the brain processes behind such bidirectional reciprocity is therefore central to social neuroscience, but this requires measurement of both individuals’ brains during real-world exchanges. We achieved this by performing functional magnetic resonance imaging (fMRI) on pairs of male individuals simultaneously while they interacted in a modified iterated Ultimatum Game (iUG). In this modification, both players could express their intent and maximise their own monetary gain by reciprocating their partner’s behaviour – they could promote generosity through cooperation and/or discourage unfair play with retaliation. By developing a novel model of reciprocity adapted from behavioural economics, we then show that each player’s choices can be predicted accurately by estimating expected utility (EU) not only in terms of immediate payoff, but also as a reaction to their opponent’s prior behaviour. Finally, for the first time we reveal that brain signals implicated in social decision making are modulated by these estimates of EU, and become correlated more strongly between interacting players who reciprocate one another.

Cognitive Processing Impacts High Frequency Intracranial EEG Activity of Human Hippocampus in Patients With Pharmacoresistant Focal Epilepsy

“…The Ultimatum Game task was previously used in an fMRI study by Shaw et al (26). It presents a simple paradigm to investigate dyadic interaction.…”

The Human Dynamic Clamp reveals the fronto-parietal network linking real-time social coordination and cognition

“…behavioral coupling with the VP) and correct attribution of the VP's intentions. Corresponding brain analysis reveals how anterior areas coordinate their activity with frontal and prefrontal areas, the latter generally recruited in decision-making tasks regardless of the presence of others (Tomlin et al, 2006;Campbell-Meiklejohn et al, 2017;Shaw et al, 2018;Thornton et al, 2019).…”

Getting into sync: Data‐driven analyses reveal patterns of neural coupling that distinguish among different social exchanges

“…A network of frontal activations incorporating the dorsal ACC and AI constitute the so-called salience network, which is thought to be responsible for identifying behaviorally relevant stimuli. In a previous study, we observed a similar pattern of neural alignment within the dorsal ACC and AI between players involved in an interactive game of economic exchange; more specifically, inter-brain alignment in these regions was associated with the degree of reciprocity expressed between players (Shaw et al, 2018). We interpreted this to reflect the mutual effort of players to modify their own behavior according to that of their opponent, a process necessary to compete successfully in an inter-dependent context.…”

“…With these techniques, studies have revealed various patterns of neural coupling elicited during social interaction; while temporally contingent brain responses are observed between interactants during verbal and non-verbal communication (Ahn et al, 2017;Bilek et al, 2015;Pérez, Carreiras, & Duñabeitia, 2017), between-brain synchrony or "alignment" (Hasson & Frith, 2016) is reported during cooperative and competitive joint-action tasks (e.g., Cheng, Li, & Hu, 2015;Sänger, Müller, & Lindenberger, 2012;Shaw et al, 2018;Toppi et al, 2016).…”