Relational models theory provides an alternative framework to study group and intergroup processes. One of four models people use to constitute groups is communal sharing (CS). Ethnographic and experimental evidence suggests that CS is produced by concrete and symbolic enactments of connections between bodies (cuddling, touching, synchronicity, commensality). We tested the effect of commensality on CS and ingroup favouritism in four Experiments with 3-person groups (total n = 330) and found that commensality enhances emergent group communal sharing but does not enhance ingroup favouritism. In Experiment 1, sharing food enhanced ingroup communal sharing but in Experiment 2 this effect was not significant. In Experiments 3 and 4, sharing water enhanced communal sharing, but only when served from the same bottle, implying consubstantial assimilation. Ingroup favouritism was not enhanced by commensality in any experiment, even when explicitly presented as exclusively ingroup (Experiment 2), suggesting non-comparative group formation through ingroup commensality.

Funding information Portuguese national science foundation (Fundação para a Ciência e Tecnologia—FCT), Grant/Award Number: PTDC/PSI/64219/2006

Commensality,Communal sharing,Ingroup favouritism,Relational models theory

• Psychology - Social Sciences