Proceedings of the Annual Meeting of the Cognitive Science Society

A speaker's use of language is one of the most important indicators in detecting deception. To date, however, little research has focused on grammatical cues used in deceitful statements. One such cue is evidentiality which is the grammatical encoding for the source of information; i.e., whether the speaker has direct or indirect access to what they assert. This study investigates whether and how evidentiality coding in Turkish, an evidential language, interacts with producing deceitful and truthful narratives. Deceptive retellings were notably longer and syntactically more complex compared to truthful counterparts. Our hypothesis of increased past forms in deception was confirmed, alongside a heightened use of direct evidential inflection (–DI) in deceptive conditions. This exploration sheds light on the nuanced relationship between grammatical evidentiality and deceptive language use.