When Patients Are Pathological Liars: Implications For Psychiatrists
Although much of the data suggest a lack of guilt about lying among psychopathic individuals, evidence does not show they are any better at it than nonpathologic individuals who choose to lie.
The concept of lying is surprisingly difficult to define, mainly because lying is not a single entity, but rather a singular manifestation of an unknown quantity of mechanisms and beliefs across an extraordinary range of circumstances.
The Stanford Encyclopedia of Philosophy writes, "There is no universally accepted definition of lying to others."1 Most definitions include several features, including both knowledge that what is being said is untrue and the intention to deceive. An added caveat to many definitions is the further intention of persuading the listener to believe the lie as well.
The Cognitive Cost of Lying
Recent examinations have concluded that lying takes work. The concept that lying is more cognitively draining than telling the truth has long been publicly believed, but in recent years it has found considerable support in clinical studies.2-4 The Activation-Decision-Construction-Action Theory proposes 4 sequential steps in the process of lying2,5:
- accessing and activation of information from long-term memory,
- making the decision to lie,
- constructing a falsehood in context with real information, and
- expressing the lie in a manner intended to persuade the listener of its truth.
All these features contribute individually and in totality to the cognitive costs of lying. Liu and colleagues2 showed that lie construction is especially taxing on working memory by using a deception task model to quantify the burden. Participants asked to lie during a high-load task had significantly lower retention measured by contralateral delay activity amplitude (which directly tracks the amount of information stored in working memory). When a low-load task was performed, there was sufficient working memory for the task while lying without decreasing contralateral delay activity, even compared with telling the truth. Both findings suggest lying competes with normal information storage and processing.2
Several methods for increasing cognitive load have proved effective as lie detection aids, including requiring continuous eye contact, asking irrelevant and distracting questions, and asking subjects to relay events in reverse order.6-8 The result of working memory overtaxation is an observable delay in response time and reduced accuracy in execution of the task.2,9
Where in the Brain Does Lying Occur?
In a meta-analysis that focused on single episodes of lying about past experiences, Christ et al.10 identified a significant overlap in brain regions serving executive function and working memory, suggesting lying may be a function of the executive control system, although the degree of involvement was not yet known. Later studies showed that high burdens on working memory activated the dorsolateral prefrontal cortex, middle frontal gyrus, precuneus, and intraparietal cortex, whereas lying activated the middle and superior frontal gyrus and precuneus. The overlapping region of the middle frontal gyrus was therefore suggested as a neural marker for successful lying.4
In a similar vein, a 2015 investigation by Ofen et al3 showed on functional magnetic resonance imaging that the frontal and parietal cortex of participants were activated in patterns that differed during the preparation and execution phases of telling of a lie. This same study also observed that variations in activation correlated to the content of the lie itself: the right temporal pole was activated more frequently in lies about episodic content (memories), whereas the precuneus was activated more frequently in lies about personal beliefs.3
Pathological vs Nonpathological Lying
Psychological distinctions are evident between people who exhibit pathological or compulsive tendencies to lie compared with psychologically normal people who choose to lie on specific occasions. The widely believed notion that psychopaths have a more natural propensity to lie and are likely to prefer lying are not borne out in studies, however. A Dutch study by Verschuere and Hout11 of 52 violent male offenders who all scored high on psychopathic rating scales found that psychopaths chose to lie only 22% of the time. Nor was the distribution of lying consistent across all participants. A subset of those considered "high grandiose-manipulative" offenders chose to lie 3 times more frequently than "low grandiose-manipulative" offenders.11
Lying is a critical clinical component of descriptions of psychopathy, and although much of the data suggest a lack of guilt about lying among psychopathic individuals, evidence does not show they are any better at it than nonpathologic individuals who choose to lie.11,12 Verschuere and Hout11 observed that in psychopathic individuals a financial penalty for lying "was coupled to slow and erroneous responding, indirectly deterring from choosing to lie."
Furthermore, offenders made nearly twice as many errors and were substantially slower in giving their answers when instructed to lie compared with telling the truth, which was consistent with rates found in studies of community samples and university students.11,13-20
But apparently, lying improves with practice. Additional research by Vershcuere and colleagues found that people who lie with regularity can learn to reduce the cognitive cost of lying (expenditure of working memory), and that only moderate amounts of practice are needed.16,21
Future studies are likely to examine the individual cognitive costs of each of the 4 components of deception on working memory storage, as well as neural locations of each of these functions, which will further clarify the mechanisms of deception. It is interesting to note that although there are differences in the reasons people lie and in the types of lies they tell, even among psychopathic individuals, there are observable effects on the working memory neural networks, which serves to validate current lie detection methods across the spectrum of lying.
In essence, lying is still more work than the telling the truth.
- Stanford Encyclopedia of Philosophy. The definition of lying and deception. https://plato.stanford.edu/entries/lying-definition/. Accessed September 11, 2017.
- Liu Y, Wang C, Jiang H, He H, Chen F. Lie construction affects information storage under high memory load construction. PLoS ONE. 2017;12(7);e0181007.
- Ofen N, Whitfield-Gabrieli S, Chai X, Schwarzlse RF, Gabrieli JDE. Neural correlates of deception; lying about past events and personal beliefs. Soc Cogn Affect Neurosci. 2017;12:116-127.
- Vartanian O, Kwantes PJ, Mandel DR, et al. Right inferior frontal gyrus activation as a neural marker of successful lying. Front Hum Neurosci. 2013;7:616.
- Walczyk JJ, Harris LL, Duck TK, Mulay D. A social-cognitive framework for understanding serious lies: Activation-decision-construction-action theory. New Ideas Psychology. 2014;34:22-36.
- Beattie GW. A further investigation of the cognitive interference hypothesis of gaze patterns during conversation. Br J Soc Psychol. 1981;20:243-248.
- Quas JA, Davis EL, Goodman GS, Myers JEB. Repeated questions, deception, and children's true and false reports of body touch. Child Maltreat. 2007;12:60-67.
- Vrij A., Fisher R., Mann S., Leal S. Detecting deception by manipulating cognitive load. Trends Cogn. Sci. 2006;10:141-142.
- Suchotzki K, Verschuere B, Van Bockstaele B, Ben-Shakhar G, Crombez G. Lying takes time: A meta-analysis on reaction time measures of deception. Psychological Bull. 2017;143:428-453.
- Christ SE, Van Essen DC, Watson JM, Brubaker LE, McDermott KB. The contributions of prefrontal cortex and executive control to deception: evidence from activation likelihood estimate meta-analyses. Cerebral Cortex. 2009;19:1557-1566.
- Verschuere B, Hout W. Psychopathic traits and their relationship with the cognitive costs and compulsive nature of lying in offenders. PLoS ONE. 11(7):e0158595.
- Verschuere B. Deception Detection: Current Challenges and New Approaches. Oxford: John Wiley & Sons, Inc. 2015. p. 269–291.
- Hare RD. Forth AE, Hart SD. The psychopath as prototype for pathological lying and deception. In: Yuille JC, eds. Credibility Assessment. Dordrecht: Nato Science; 1989.
- Spence SA, Farrow TFD, Herford AE, Wilkinson ID, Zheng Y, Woodruff PWR. Behavioural and functional anatomical correlates of deception in humans. Neuroreport. 2001;12:2849-2853.
- Verschuere B, Suchotzki K, Debey E. Detecting deception through reaction times. In: Granhag PA, Vrij A, Verschuere B. Deception Detection: Current Challenges and New Approaches. Oxford: John Wiley & Sons; 2015. pp. 269-291.
- Verschuere B, Spruyt A, Meijer EH, Otgaar H. The ease of lying. Conscious Cogn. 2011;20:908-911.
- Debey E, Verschuere B, Crombez G. Lying and executive control: An experimental investigation using ego depletion and goal neglect. Acta Psychol. 2012;140:133-141.
- Spence SA, Kaylor-Hughes CJ. Looking for truth and finding lies: The prospects for a nascent neuroimaging of deception. Neurocase. 2008;14:68-81.
- Van Bockstaele B, Verschuere B, Moens T, Suchotzki K, Debey E, Spruyt A. Learning to lie: Effects of practice on the cognitive cost of lying. Front Psychol. 2012;3:526.
- Van Bockstaele B, Wilhelm C, Meijer E, Debey E, Verschuere B. When deception becomes easy: The effects of task switching and goal neglect on the truth proportion effect. Front Psychol. 2015;6:1666.
- Van Bockstaele B, Verschuere B, Moens T, Suchotzki K, Debey E, Spruyt A. Learning to lie: effects of practice on the cognitive cost of lying. Front Psychol. 2012;3:526.