Recent examinations have concluded that lying takes work. The concept that lying is more cognitively draining than telling the truth has long been publicly believed, but in recent years it has found considerable support in clinical studies.2-4 The Activation-Decision-Construction-Action Theory proposes 4 sequential steps in the process of lying2,5:
- accessing and activation of information from long-term memory,
- making the decision to lie,
- constructing a falsehood in context with real information, and
- expressing the lie in a manner intended to persuade the listener of its truth.
All these features contribute individually and in totality to the cognitive costs of lying. Liu and colleagues2 showed that lie construction is especially taxing on working memory by using a deception task model to quantify the burden. Participants asked to lie during a high-load task had significantly lower retention measured by contralateral delay activity amplitude (which directly tracks the amount of information stored in working memory). When a low-load task was performed, there was sufficient working memory for the task while lying without decreasing contralateral delay activity, even compared with telling the truth. Both findings suggest lying competes with normal information storage and processing.2
Several methods for increasing cognitive load have proved effective as lie detection aids, including requiring continuous eye contact, asking irrelevant and distracting questions, and asking subjects to relay events in reverse order.6-8 The result of working memory overtaxation is an observable delay in response time and reduced accuracy in execution of the task.2,9