Sevilay Sengul Defended Her Master's Thesis

Thesis Title: Neural Processing of Negation with Prosody and Gesture: The Case of Turkish 

In her thesis, Sevilay explores how prosody and gestures may influence the comprehension of negation markers in Turkish, an agglutinative language with a verb-final structure. Previous research has shown that both prosody and gestures can independently facilitate speech perception, as evidenced by reduced N400 amplitudes in EEG studies. Building on these findings, her study examines whether Turkish-specific gestures (e.g., the negation hand flip) and lexical stress can predict the occurrence of the negation suffix "-mA" following the main verb.

To address this, she employed a mixed-method approach: a corpus analysis of informal conversations on YouTube and an EEG experiment with Turkish-speaking participants. The corpus analysis revealed prevalent prosodic and gestural patterns co-occurring with verbs preceding negation, suggesting that the stress shift and gesture could signal negation to listeners. However, the EEG experiment showed no modulation of ERP responses when negation was preceded by prosody and/or gestures, suggesting that these cues did not have an observable effect on the neural processing of negation markers in this context.