Postural configurations as micro-ecological constraints: How embodied arrangements shape the emergence of...

How do embodied configurations shape the emergence of communication? We investigated how bodily-visual communication develops under two interactional arrangements: standing-open and seated-at-table. Seventy dyads (140 participants) created novel speech-free signals for 32 meanings across three rounds of a referential communication task while their movements were recorded using high-resolution motion capture. Across both configurations, dyads showed robust efficiency dynamics: communicative success increased, movement path and volume decreased, articulatory specialisation intensified, and kinematic alignment between interlocutors increased. Configuration effects, however, were expressed most clearly in the movement-based measures rather than in communicative success. Success improved rapidly in both configurations, with only weak and transient evidence for an early standing-open advantage. By contrast, seated-at-table interaction promoted more compact movements and digital specialisation, whereas standing-open interaction involved larger movements and progressive brachiomanual specialisation. The pathways towards similar levels of alignment were also different: participants in the standing-open configuration converged in a linear fashion, whereas seated-at-table dyads converged rapidly by mid-experiment, then relaxed to the level ultimately reached in the standing-open configuration. These findings suggest that embodied arrangements do not primarily determine whether communication becomes successful, but they do shape how communicative efficiency is realised in bodily movement.