PLOS ONE

Previous studies demonstrated that lying could undermine memory, and the memory-undermining effects could be modulated by the cognitive resources required to tell the lie. We extended the investigation of the memory-undermining effect by using a daily-life paradigm in which participants were highly involved in a mock shopping task. Participants were randomly assigned to either the truth-telling, simple lying or complex lying condition. After finishing the shopping task, participants were told that two people wanted to know about their shopping lists and would ask them some questions in an interview. During the interview, participants in the truth-telling group were asked to respond honestly, those in the simple lying group were needed to give negative responses to all questions, and those in the complex lying group were required to respond deceptively. The item memory test, source memory test and destination memory test were given orderly 48 hours after the interview. We found that participants in the lying groups forgot the lies they told in the interview, and those in the complex lying group mistakenly believed they had lied about something. Moreover, the complex lying group retained fewer memories about the person they lied to. In addition, participants in the complex lying group had more nonbelieved memories than those in the truth-telling group. We conclude that more cognitive resources consumed in lying could result in more memory impairments in daily life.