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“Mmm… They look so good”: TDCS influences sarcasm evaluation and gaze patterns in the right TPJ
Poster Session B, Friday, September 12, 4:30 - 6:00 pm, Field House
Rose Baker1, Peyton Disser1, Essence Hopkins1, Anna Abernathy1, Katherine Palin1, Moritz Dannhauer1, Katherine Rothermich1; 1East Carolina University
Background: Neural processing of Theory of Mind (ToM) and cognitive empathy has been consistently linked to activity in the right temporoparietal junction (rTPJ). These social-cognitive abilities also support pragmatic language comprehension. In the current study, we test the hypothesis that the rTPJ plays a critical role in understanding pragmatic language, including sarcasm and teasing. Methods: This study examines how rTPJ inhibition via transcranial Direct Current Stimulation (tDCS) influences pragmatic processing while accounting for individual differences. First, participants receive 20 minutes of cathodal tDCS (1.5 mA or sham) to transiently reduce cortical excitability in the rTPJ. Participants then evaluated sarcastic, teasing, and sincere interactions while seated at an eye tracker. The stimuli consisted of 96 dynamic video interactions drawn from the Relational Inference in Social Communication (RISC) database. Primary measures include fixation count and duration towards target speakers’ faces, accuracy a sincerity question, friendliness of the interaction, and reaction time. Participant also filled out surveys about their personality, anxiety, empathy, psychopathy, and sarcasm use to model individual differences in eye tracking patterns and behavioral response. Results: Preliminary analyses indicate that the effect of rTPJ inhibition on pragmatic language processing is moderated by individual differences in empathic concern. Participants with high empathic concern exhibited slower reaction times under tDCS compared to sham stimulation, suggesting that reduced rTPJ excitability disrupted efficient integration of speaker intent. In contrast, those with low empathic concern responded more quickly following tDCS, potentially reflecting shifts in processing strategy. Reaction time change scores followed three broad patterns: positive changes (slower responses under tDCS), negative changes (faster responses), and near-zero changes (minimal or variable effects). Notably, slower responses under tDCS were accompanied by increased visual scanning of speaker faces, suggesting greater cognitive effort during social interpretation when rTPJ function was inhibited. Conclusion: These findings support a role for the rTPJ in pragmatic language comprehension, particularly in interpreting socially complex, nonliteral speech. The results also suggest that empathy modulates how individuals adapt to neural disruption, probably through distinct compensatory strategies across participants. Increased visual attention to social cues during tDCS suggests that when typical inferential processes are disrupted, individuals may rely more heavily on visual information to interpret speaker intent. This study advances understanding of the neural basis of pragmatic reasoning and sets the stage for future investigations in clinical populations with social-cognitive impairments.
Topic Areas: Meaning: Discourse and Pragmatics, Speech Perception