The Effects of Depleting Executive Cognitive Control on Deception Ability

Lying is cognitively more demanding than truth telling because of the various concurrent tasks that need to be performed to be deceitful (e.g., suppressing the automatic truth response, appearing truthful, etc.). The objective of this study is to test the cognitive load hypothesis (CLH). The premise of the CLH is that adding mental load during lying or truth telling will challenge the liar more than the truth teller. This should lead to greater differences between these two groups and improvement in observers’ lie detection accuracy. To the test the CLH, we had participants perform a control or cognitive depletion task (which is well-known to impair performance on subsequent tasks requiring greater access to mental resources). Subsequently, participants lied or told the truth during a video-taped interview. We hypothesized that those in the depletion condition will perform worse on the manipulation task and less well during lying than those in the control condition. The depletion manipulation had the intended effect; results show that those in the depletion condition were slower at responding and made more errors than those in the control condition. Interview performance and observers’ accuracy in discriminating between truths and lies will be assessed. This is the first study to test the CLH using tasks that directly undermine key cognitive processes involved in deception and uses a more real-world interview paradigm. As such the results of this study informs theory and also addresses applied concerns as there is a need for theory-based lie detection methods.