Lexical alignment persists across a 12 h interval but is unaffected by sleep versus wake.

Sleep may play a key role in consolidating social interactions by transforming brief communicative experiences into stable social memories. In this paper, we used the lexical alignment task to investigate whether sleep enhances the consolidation of shared linguistic representations between partners. Lexical alignment, where participants converge their word choices with those produced by a partner, served as a marker of successful communication and shared understanding. Eighty-two participants completed a picture-matching and picture-naming task before and after 12 h of sleep or wake. Results showed the lexical alignment effect persisted 12 h after the initial picture-matching interaction. However, this effect was not influenced by whether participants slept or remained awake during the retention interval. These findings suggest that while participants encoded enduring representations of partner-specific lexical information during interaction, sleep-based consolidation did not confer an additional benefit. One possibility is that a higher level of social relevance is needed for these memories to be susceptible to sleep consolidation. Alternatively, limited hippocampal involvement during encoding may have reduced the extent to which information was reactivated during sleep. Future research should employ richer and more interactive tasks to clarify how sleep supports the consolidation of social experiences and relationship perceptions.