Want to lie convincingly? Get practicing!

Lying, the deliberate attempt to mislead someone, is a processes that we all engage in at some time or another. Indeed research has found that the average person lies at least once a day, suggesting that lying is a standard part of social interaction (1). Despite its common occurrence lying is not an automatic process. Instead it represents an advanced cognitive function; a skill that requires more basic cognitive abilities to be present before it can emerge. To lie an individual first needs to be able to appreciate the benefits of lying (e.g. a desire to increase social status) so that they have the motivation to behave deceitfully. Successful lying also requires ‘theory of mind’ or the ability to understand what another person knows. This is necessary so that the would-be liar can spot firstly the opportunity to lie, and secondly what sort of deception might be required to produce a successful lie. Finally lying also requires the ability to generate a plausible and coherent, but nonetheless fabricated description of an event. Given these prerequisites it is unlikely that we are ‘born liars’. Instead the ability to lie is believed to develop sometime between the ages of 2 and 4 (2). The fact that the ability to lie develops over time suggests that the our performance of the ‘skill’ of lying should be sensitive to practice. Do people who lie more often become better at it?

Lying is tiring!
Lying is considered more cognitively demanding that telling the truth due to the extra cognitive functions that need to be utilised to produce a lie. The idea that lying is cognitively demanding is supported both by behavioural data showing that deliberately producing a  misleading response takes longer, and is more prone to error, than producing a truthful response (3) and by neurological data showing that lying requires additional activity in the prefrontal areas of the brain when compared to truth telling (4). These observable differences between truth telling and lying allow a measure of ‘lying success’ to be created. For example a successful, or skilled liar, should be able to perform lies more quickly and accurately than a less successful liar, perhaps to the extent that there is no noticeable difference in performance between truth telling and lying in such individuals. Likewise, if the ability to lie is affected by practice, then practice should make lies appear more like the truth in terms of behavioural performance.

Practice makes perfect (but is this a lie)?
Despite the intuitive appeal of the idea that lying becomes easier with practice, much past research has failed to find an effect of practice on lying, either when measuring behavioural (3) or neuroimaging (5) markers of lying. Such results have led to the conclusion that lying may always be significantly more effortful than truth telling, no matter how practiced an individual is at deception.

A recent study (6) has re-examined this issue. They used a version of the ‘Sheffield Lie Test’ where participants are presented with a list of questions that require a yes/no response (e.g. ‘Did you buy chocolate today?’). The experiment involved three main phases. In the first, baseline phase, participants were required to respond truthfully to half the statements and to lie in response to the other half of the statements. In the middle, training phase, the statements were split into two groups. For a control group of statements the proportion that required a truthful response remained at 50% for all participants. For an experimental group of statements the proportion that required a truthful response was varied between participants. Participants either had to lie in response to 25%, 50% or 75% of these statements, thus giving the participants differing levels of ‘practice’ at lying. The final, test phase, was a repeat of the baseline phase. This design allowed two research questions to be assessed. Firstly the researchers could identify whether practice at lying reduced the ‘lie effect’ on reaction time and error rate (e.g. the increased reaction time and error rate that occurs when a participant is required to lie, compared to when they are required to tell the truth). Secondly the researchers could identify whether any reduction in the lie effect applied just to the statements on which the groups had experienced differing practice levels, or whether it also generalised to those statements where all groups had the same level of practice.

The results revealed that practice did produce an improvement in the ability to lie during the period when the training was actually taking place, and that this improvement applied to both the control statements and the experimental statements. The participants who had to lie more demonstrated reduced error rates and reaction times compared to those who had to lie less during the training phase. However in the test phase this improvement was only maintained for the set of statements where the frequency of lying had been manipulated. The group who had practiced lying on 75% of the experimental statements were no faster or more accurate at lying on the control statements than the group who had to lie in response to just 25% of the experimental statements. These results suggest that practice can make you better at lying, but this improvement is only sustained over time for the specific lies that you have rehearsed.

Some lies may be better than others!
One important criticism of most studies on the effect of practice on lying is that they tend to use questions or tasks that require binary responses (i.e. yes/no questions). However in real life lying often involves the concoction of complex false narratives,a form of lying that is likely to be far more cognitively demanding than just saying ‘No’ in response to a question whose answer is ‘Yes’. Likewise the lies tested in laboratory studies tend to be rehearsed, or at least prepared lies. In contrast many real-life lies are concocted at short notice, with the deceptive narrative being constructed in ‘real-time’, whilst the person is in the process of lying. It is likely that the effect of training, and how that training generalises to other lies, will be different for these more advanced forms of lying than it is for the more simple types of lies that tend to be tested under laboratory conditions. Given this, if a psychologist tells you that we know for certain how practice impacts on the ability to deceive, you can be sure that they are lying!



(1) DePaulo, B.M., Kashy, D.A., Kirkendol, S.E., Wyer, M.M. & Epstein, J.A. (1996) Lying in everyday life. Journal of Personality and Social Psychology, 70 (5) 979-995. http://smg.media.mit.edu/library/DePauloEtAl.LyingEverydayLife.pdf
(2) Ahern, E.C., Lyon, T.D. & Quas, J.A. (2011) Young Children’s Emerging Ability to Make False Statements. Developmental Psychology. 47 (1) 61-66. http://www.ncbi.nlm.nih.gov/pubmed/21244149
(3) Vendemia, J.M.C., Buzan,R.F., & Green,E.P. (2005) Practice effects, workload and reaction time in deception. American Journal of Psychology. 5, 413–429. http://www.jstor.org/discover/10.2307/30039073?uid=3738032&uid=2129&uid=2&uid=70&uid=4&sid=21101917386241
(4)Spence, S.A. (2008) Playing Devil’s Advocate: The case against MRI lie detection. Legal and Criminological Psychology 13, 11-25. http://psychsource.bps.org.uk/details/journalArticle/3154771/Playing-Devils-advocate-The-case-against-fMRI-lie-detection.html
(5) Johnson,R., Barnhardt,J., & Zhu, J.(2005) Differential effects of practice on the executive processes used for truthful and deceptive responses: an event-related brain potential study. Brain Research: Cognitive Brain Research 24, 386–404. http://www.ncbi.nlm.nih.gov/pubmed/16099352
(6) Van Bockstaele, B., Verschuere, B., Moens, T., Suchotzki, K., Debey, E. & Spruyt, A. (2012) Learning to lie: effects of practice on the cognitive cost of lying. Frontiers in Psychology, November (3) 1-8. http://www.ncbi.nlm.nih.gov/pubmed/23226137

Rob Hoskin

Received a PhD from the Neuroscience Department of Sheffield University. Views expressed in blog posts do not necessarily represent the views of the Science Brainwaves organisation. https://twitter.com/Hoskin_R

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