The project examines the role of working memory capacity (WMC) in lying. WMC is the ability to use focused attention and cognitive effort to accomplish goals. Anything that requires attention and concentration will use WMC. Research indicates that lying may require more WMC than telling the truth because lying requires suppressing truthful information, generating a lie to tell, and telling that lie in a believable way, among other cognitive tasks. In comparison, telling the truth primarily requires recall of information. Previous research shows that liars display some behaviors which indicate cognitive load. When liars and truth tellers are placed under extra cognitive load, such behaviors become more pronounced in liars compared to truth tellers. These behaviors can be used to more accurately distinguish liars from truth tellers. The current research will examine how this finding is affected by WMC, as research has shown that WMC is related to an individual?s ability to cope with cognitive load. In Studies 1 and 2 participants will lie or tell the truth either under cognitive load or no cognitive load. WMC will be measured to examine its impact on verbal, vocal, and visual behavior. In Study 3, observers will judge the truthfulness of participants from Studies 1 and 2. This project will help advance the understanding of how working memory affects deception, specifically whether individuals with greater WMC are better at coping with cognitive load during lying. This project will also expand research on individual differences in the deception field by studying how variation in a particular cognitive capacity affects deceptive behavior.
Learning more about lying and truth telling can aid law enforcement and other groups who face the task of judging credibility in their professional life. This research can be used to help develop methods of lie detection that exploit the cognitive processes of liars. In addition, this project will contribute to the training of a graduate student.
Main Findings We found an impact of interview style on cognitive load. Those interviewed under a normal interview style (Normal Order) exhibited fewer cues to cognitive load than those interviewed by giving their statements backwards (Reverse Order) or while performing a simultaneous task (Dual Task). There was also an effect of deception on cognitive load. Those participants telling the truth exhibited fewer cues to cognitive load compared to those told to tell a lie by either pretending that something they did earlier was what they had done during the time of the theft (truthful lie) or by fabricating details about what they did during the theft (constructed lie). We did not however, find any impact of working memory capacity (WMC). As lie detection, overall accuracy was very low at 41%. There was an impact on accuracy due to deception. Participants asked to judge a truthful statement had higher accuracy than those asked to judge a truthful lie or a constructed lie. There was an interaction between deception and interview type. Under Normal Order and Reverse Order, participants’ accuracy for truth was much better than for lies, however in Dual Task, participants accuracy for truth was worse than in the other interview conditions. Intellectual Merit The main goal of this research project was to examine the effect of WMC, however we did not find any such effects. Though we did not find what we expected, the lack of effect is still useful information for understanding deception. As it seems that WMC does not affect the formation of cues to cognitive load, it may not be related to deception. It may be that the effect of the interview and the effect of deception have more impact on the formation of cognitive load than does the effect of WMC. Essentially, WMC is not a powerful predictor of how well a person is able to lie. This finding may also say something about the nature of human lie telling behavior. It may be that humans are so well practiced at deceit that not much WMC is needed to devote to the task. Thus the exhibition of cues to cognitive load may depend more an individual person’s practice at lying and rehearsal of lies than in their cognitive ability. The effects we did find also have implications for the broader field. First of all, we confirmed previous findings that deception and cognitively demanding interview methods increase cues to cognitive load. This suggests that the process of deception is more cognitively demanding than that of telling the truth and likewise that it is possible to impose additional cognitive load through the process of the interview itself. However, we did not find that truth tellers were more protected from the effects of the cognitive imposition of the interview. So it would seem that while truth telling is less cognitively difficult, it is not so easy that it cannot be interfered with by the process of the interview. This indicates that telling the truth is not just the recitation of a memory, but also includes other elements that impose cognitive demand. Finally, it is worth noting that we had two different types of deception, but the pattern of results for some indicators of cognitive load was not always uniform for both types of deception. In some cases, one type of lie behaved more similarly to the truth than it did to the other lie. This indicates that some lies can be told to minimize the effect of their cognitive demand, thus making them seem more like truthful statements. This is also very interesting because it further supports our interpretation that telling the truth does impose some cognitive demand. Taken together, this aids in the understanding of the process of telling a lie and telling the truth. Both impose some amount of cognitive load, but it is possible to structure a lie such that it involves less cognitive demand and thus appears closer to the truth. Broader Impact The findings of this study have implications for many individuals in the field who need to assess truth and deceit. These findings suggest that the use of interview techniques that impose cognitive load on individuals may not be helpful in the ability to accurately detect lies and truths. In fact it may even be detrimental. Under no circumstances were imposed cognitively demanding interview methods helpful at detecting liars, and under conditions of Dual task, it actually masked the truthfulness of the truth tellers. It may be that imposing too much cognitive demand can make truth tellers appear deceptive. A much more thorough understand of the imposition of cognitive difficulty should be in place before practioners attempt to use these types of interview methods.
