Impact of the gut microbiome composition on social decision-making

Marie Falkenstein (1) , Marie-Christine Simon (2) , Aakash Mantri (2) , Bernd Weber (3) , Leonie Koban (4, 5) , Hilke Plassmann (6, 1)

1 ICM - Institut du Cerveau = Paris Brain Institute
2 Universität Bonn = University of Bonn
3 CENs - Center for Economics and Neuroscience, University of Bonn, Bonn
4 CRNL - Centre de recherche en neurosciences de Lyon - Lyon Neuroscience Research Center
5 CNRS - Centre National de la Recherche Scientifique
6 INSEAD - Institut Européen d'administration des Affaires

There is increasing evidence for the role of the gut microbiome in the regulation of socio-affective behavior in animals and clinical conditions. However, whether and how the composition of the gut microbiome may influence social decision-making in health remains unknown. Here, we tested the causal effects of a 7-week synbiotic (vs. placebo) dietary intervention on altruistic social punishment behavior in an ultimatum game. Results showed that the intervention increased participants’ willingness to forgo a monetary payoff when treated unfairly. This change in social decision-making was related to changes in fasting-state serum levels of the dopamine-precursor tyrosine proposing a potential mechanistic link along the gut–microbiota–brain-behavior axis. These results improve our understanding of the bidirectional role body–brain interactions play in social decision-making and why humans at times act “irrationally” according to standard economic theory.

Mots clés: ultimatum game; microbiome; social decision-making; gut-brain axis

Domaines: Sciences cognitives; Neurosciences [q-bio.NC]

Marie Falkenstein, Marie-Christine Simon, Aakash Mantri, Bernd Weber, Leonie Koban, et al.. Impact of the gut microbiome composition on social decision-making. PNAS Nexus, 2024, 3 (5), ⟨10.1093/pnasnexus/pgae166⟩. ⟨hal-04578634⟩