Proceedings of the Annual Meeting of the Cognitive Science Society

How do interlocutors achieve mutual understanding when communicative mappings are not given in advance? We propose that meaning-making is a symmetry-breaking constructive process: through interaction, dyads compress an open space of communicative possibilities into a low-dimensional set of shared alternatives, namely dyad-specific signal-referent relations that enable coordination. We test this account in 69 dyads using a real-time semiotic game in which participants invent and stabilize dyad-specific communicative conventions, modeling signal–referent relations with spectral graph thermodynamics. Successful dyads exhibited dimensional compression of their signaling space: intrinsic dimensionality was reduced sixfold relative to random networks, reflecting the emergence of stabilized dyad-specific conventions. These dyads also showed lower thermodynamic efficiency, indicating that constructing shared signal–referent structure carries an entropy cost. Thermodynamic and geometric measures converged at a mesoscale diffusion regime, where relational constraints operate. These findings suggest that mutual understanding depends on actively constructing a shared, low-dimensional communicative structure through interaction.