Ad-hoc thematic relations form through communication: effects on lexical-semantic processing during language production

In this preregistered study, we investigate whether themes conveyed by task partners’ narratives reveal semantic relationships between objects that would otherwise be perceived as unrelated. Such ad-hoc formation of thematic relations should result in semantic interference when naming objects related to the theme in a blocked-cyclic naming paradigm. Participants watch pre-recorded videos of presumed partners narrating real-life events, and then name pictures either thematically related or unrelated to the narrative. Experiments 1 and 2 (N = 32 each) demonstrate semantic interference between objects related to the partner's narrative. Interestingly, this effect emerges only when unrelated pictures are named first. Interference is greatly attenuated, or even turns into facilitation when related pictures are named directly after the partner's narrative. Experiment 3 (N = 32) confirms that semantic context effects disappear when the objects cannot be related to the narrative. Our results demonstrate how flexible semantic processing adapts to context communicated by a task partner.