Learning to Lie: Effects of Practice on the Cognitive Cost of Lying

Abstract

Cognitive theories on deception posit that lying requires more cognitive resources than telling the truth. In line with this idea, it has been demonstrated that deceptive responses are typically associated with increased response times and higher error rates compared to truthful responses. Although the cognitive cost of lying has been assumed to be resistant to practice, it has recently been shown that people who are trained to lie can reduce this cost. In the present study (n = 42), we further explored the effects of practice on one’s ability to lie by manipulating the proportions of lie and truth-trials in a Sheffield lie test across three phases: Baseline (50% lie, 50% truth), Training (frequent-lie group: 75% lie, 25% truth; control group: 50% lie, 50% truth; and frequent-truth group: 25% lie, 75% truth), and Test (50% lie, 50% truth). The results showed that lying became easier while participants were trained to lie more often and that lying became more difficult while participants were trained to tell the truth more often. Furthermore, these effects did carry over to the test phase, but only for the specific items that were used for the training manipulation. Hence, our study confirms that relatively little practice is enough to alter the cognitive cost of lying, although this effect does not persist over time for non-practiced items.

Lying relies on the truth

“…Self-reports do show that the truth is also used when lying to open-ended questions (Walczyk et al, 2003), but additional experimental research on this issue seems warranted. Although our participants lied several times to the same questions, we cannot speak of extended lie training (e.g., Van Bockstaele et al, 2012;Verschuere et al, 2011). It is possible that lying does no longer involve a two-step process when a lie has been extensively practiced.…”

Reaction time measures in deception research: Comparing the effects of irrelevant and relevant stimulus–response compatibility

“…Developed as an experimental manipulation of truth telling and lying, the paradigm has mainly been used in fundamental research about the cognitive processes underlying lying, and provides reliable lie-truth differences (e.g., Debey et al 2012;Farrow et al 2010;Fullam et al 2009;Hu et al, 2012a;Spence et al, 2001;Van Bockstaele et al 2012;Verschuere et al , 2012). This relevant SRC task has, however, rarely been applied to discriminate between guilt and innocence.…”

The cognitive mechanisms underlying deception: An event-related potential study

“…By lying and telling the truth on the same set of questions, each stimulus forms its own control. In line with the view that lying is cognitively more demanding than truth telling, behavioral studies using this paradigm have consistently shown that lying is more error-prone than truth telling and associated with longer and more variable response latencies Farrow et al, 2010;Fullam et al, 2009;Hu et al, 2012;Van Bockstaele et al, 2012;. In our version of the Sheffield Lie Test, participants gave speeded yes/no responses to mock-crime and control questions using left and right button presses.…”