Von Hippel & Trivers (VH&T) consider self-deception as an offensive strategy evolved for deceiving others. Via self-deception, people can convince themselves that their lies are true, and consequently, they will no longer emit the cues of consciously mediated mendacity that could reveal their deceptive intent. Indeed, people who deceive themselves and do not display deception cues are difficult to catch, but it tells us nothing about lying skills because they are not lying. Lying is “a deliberate attempt to mislead others,” and “falsehoods communicated by people who are mistaken or self-deceived are not lies” (DePaulo et al. Reference DePaulo, Wetzel, Weylin Sternglanz and Walker Wilson2003, p. 74).

VH&T describe different ways in which people can deceive themselves, including through “biased information search” (avoiding further information search, selective information search, and selective attention to available information), “biased interpretation of information,” and “misremembering [information].” This means that they take into account only a few of the vast number of lies people can tell. How can a suspect who burgled a house last night and is interviewed by the police use such mechanisms? Or the man who has returned home late from work after talking to his female colleague and then is asked by his wife why he is late? (VH&T's example). They cannot.

VH&T report that “people are actually quite good at detecting deception.” Research does not support this claim (Bond & DePaulo Reference Bond and DePaulo2006; Vrij Reference Vrij2008). However, VH&T argue that lie detection research may have grossly underestimated people's ability to detect deception because it relies on conditions that “heavily advantage the deceiver.” Those conditions include (1) the deceiver being unknown to the lie detector and (2) no opportunity to question the deceiver. Other conditions, however, give advantage to lie detector, so that they are aware that they may be lied to. One important reason why lies in daily life remain undetected is that people tend to be credulous (DePaulo et al. Reference DePaulo, Wetzel, Weylin Sternglanz and Walker Wilson2003; Vrij Reference Vrij2008). It makes sense to be credulous, as people are more often confronted with truths than lies (DePaulo et al. Reference DePaulo, Kashy, Kirkendol, Wyer and Epstein1996), but it hampers lie detection. The tendency to judge others as truthful becomes stronger as relationships become more intimate (Levine & McCornack Reference Levine and McCornack1992; McCornack & Parks Reference McCornack, Parks and McLaughlin1986; Stiff et al. Reference Stiff, Kim and Ramesh1992). This could explain why research has shown that people are no better in detecting lies in friends or partners than in strangers (negating VH&T's claim). In fact, none of the studies where a direct comparison was made between the ability to detect truths and lies in strangers versus in friends or partners found a difference in accuracy rates (Anderson et al. Reference Anderson, DePaulo and Ansfield2002; Buller et al. Reference Buller, Strzyzewski and Comstock1991; Fleming et al. Reference Fleming, Darley, Hilton and Kojetin1990; Millar & Millar Reference Millar and Millar1995). One reason why no link between relationship closeness and accuracy at detecting deception seems to exist is that when close relationship partners attempt to detect deceit in each other, they bring to mind a great deal of information about each other. This information could be overwhelming, and the lie detector may deal with this by processing the information heuristically instead of carefully searching for genuine cues to deceit. Another explanation is that as relationships develop, people become more skilled at crafting communications uniquely designed to fool each other (Anderson et al. Reference Anderson, Ansfield, DePaulo, Philippot, Feldman and Coats1999).

There is no evidence either that the ability to interview in itself facilitates lie detection, as VH&T suggest (see Vrij Reference Vrij2008 for a review of those studies). It depends on how the interviews are conducted. In one experiment truth tellers went to a shop and bought an item that was hidden under a briefcase. Liars took money out of the briefcase. Therefore, both truth tellers' and liars' fingerprints were found on the briefcase. Swedish police detectives were given this fingerprint evidence and were requested to interrogate the suspect in the style of their choice. They obtained 56.1% accuracy. In contrast, police detectives who were taught an innovative interrogation technique aimed at using the piece of evidence strategically during the interrogation (by asking questions about the evidence without revealing it) obtained 85.4% accuracy (Hartwig et al. Reference Hartwig, Granhag, Strömwall and Kronkvist2006).

Recent research revealed another way to detect lies via strategic interviewing. As VH&T correctly argue, liars experience more cognitive load than truth tellers. A lie catcher could exploit the differential levels of cognitive load to discriminate more effectively between them. Liars who require more cognitive resources than truth tellers will have fewer cognitive resources left over. If cognitive demand is further raised, which could be achieved by making additional requests, liars may have more difficulty than truth tellers in coping with these additional requests.

Ways to impose cognitive load include asking interviewees to tell their stories in reverse order or instructing them to maintain eye contact with the interviewer. In two experiments, half of the liars and truth tellers were requested to recall their stories in reverse order (Vrij et al. Reference Vrij, Mann, Fisher, Leal, Milne and Bull2008) or to maintain eye contact with the interviewer (Vrij et al. Reference Vrij, Mann, Leal and Fisher2010), whereas no instruction was given to the remaining participants. More cues to deceit emerged in the reverse order and maintaining eye contact conditions than in the control conditions. Observers who watched these videotaped interviews could distinguish between truths and lies better in the reverse order condition and maintaining eye contact conditions than in the control conditions. Vrij et al. (Reference Vrij, Mann, Leal and Fisher2010; in press) provided overviews of interviewing to detect deception research.

VH&T suggest future research examining how people detect lies in daily life. Such research has already been conducted (Park et al. Reference Park, Levine, McCornack, Morrisson and Ferrara2002). Less than 2% of the lies were detected at the time the lie was told by relying exclusively on the liars' nonverbal behavior or speech content. Lies were mostly discovered via information from third parties (38%), physical evidence (23%), and confessions (14%).

In summary, VH&T's view that people who deceive themselves are lying can be challenged, and so can their view that people are quite good at detecting lies. People become better lie detectors by employing interview techniques aimed at strategically using the available evidence or by imposing cognitive load on the interviewees.