What is retained about common ground? Distinct effects of linguistic and visual co-presence

Common ground can be mutually established between conversational partners in several ways. We examined whether the modality (visual or linguistic) with which speakers share information with their conversational partners results in memory traces that affect subsequent references addressed to a particular partner. In 32 triads, directors arranged a set of tangram cards with one matcher and then with another, but in different modalities, sharing some cards only linguistically (by describing cards the matcher couldn't see), some only visually (by silently showing them), some both linguistically and visually, and others not at all. Then directors arranged the cards again in separate rounds with each matcher. The modality with which they previously established common ground about a particular card with a particular matcher (e.g., linguistically with one partner and visually with the other) affected subsequent referring: References to cards previously shared only visually included more idea units, words, and reconceptualizations than those shared only linguistically, which in turn included more idea units, words, and reconceptualizations than those shared both linguistically and visually. Moreover, speakers were able to tailor references to the same card appropriately to the distinct modality shared with each addressee. Such gradient, partner-specific adaptation during re-referring suggests that memory encodes rich-enough representations of multimodal shared experiences to effectively cue relevant constraints about the perceptual conditions under which speakers and addressees establish common ground.