Behind the scenes of lying - cognitive and emotional processes revealed by reaction times and self-reports.

While lying is assumed to be cognitively and emotionally demanding, empirical research has primarily focused on cognitive mechanisms. The current study therefore examined cognitive and emotional components of lying simultaneously, using self-reports and reaction times. In two preregistered experiments (n = 49; n = 48), participants conducted a modified version of the Sheffield Lie Test, providing truthful and deceptive responses to neutral and mock-crime-related questions. After each block, participants rated their cognitive and emotional load, as well as specific subprocesses. Results revealed robust main effects of instruction and question type. Lying led to longer reaction times and higher self-reported cognitive and emotional load than telling the truth, and the same was true for mock-crime-related compared to neutral questions. No interaction was observed. Subjective ratings indicated that the most pronounced cognitive processes during lying were response inhibition and task switching, and nervousness and fear the emotional ones. These findings extend previous research by providing strong evidence that lying is not only cognitively but also emotionally demanding, highlighting the need for a comprehensive theoretical framework that integrates both mechanisms. It also provides first information which specific cognitive and emotional processes may be the most relevant.