Lying and what drives people to lie

By Naveesha Karunanayaka

There is no one definition for a lie, however the Cambridge dictionary defines one as speaking falsely. The act of lying is to “say or write something that is not true in order to deceive someone”.1 It involves two parties: the deceiver and the deceived. Although the deceiver is the one actively communicating false pretences, the deceived must also participate in the lie on some level, whether this be due to apathy, ignorance, bias, or overconfidence.2 People lie to varying degrees and for different reasons. The context and motivations behind such actions are then judged when a lie unravels, dictating its severity and consequences.

Lies generally manifest as one of the following paradigms of dishonesty: Complete DeceptionHalf-TruthsExaggerations; and Pertinent Omissions.2  Accordingly, dishonesty may be brought on when the deceiver believes there is more to gain from lying than there is to lose from telling the truth, or when they are unable to discern what the truth is – either temporarily or due to psychological defects.2

Most lies are told for self-serving purposes. They allow us to save face, avoid hurting others, impress others, hide misdeeds and prevent conflict. When a lie is told, the deceiver is taking advantage of the human tendency to believe others.2 Subsequently, there are two directions this deception leads: either nothing comes of it due to its lack of severity and malicious intent, usually named a white lie; or it can lead to more palpable consequences, occasionally greater than the deceiver intends. Indeed, the worst lies can sometimes have definite and immediate consequences, destroying businesses or governments, ruining relationships, or even risking people’s lives.

Taking romantic relationships as an example, lies can have a huge impact because of how intertwined two people’s lives can become. Not only can they affect a person’s emotional well-being but also their economic situation, daily behaviours, routine, friends (which you often come to share), and interactions with others. Nevertheless, past studies lead by Dr. Bella DePaulo, from the University of California at Santa Barbara, have demonstrated that dating couples lie to each other in around a third of their interactions, possibly more often than they deceive others.3 According to her, more impactful lies that involve betrayal and the loss of trust are often saved for our most intimate relationships, for the ones closest to us.

Differences have also been observed in lies told by men and women. Women tend to be altruistic in their lies, for example, often stretching the truth to protect someone else’s feelings. Comparatively, men’s lies are typically more self-interested, usually intended to protect themselves.5

It was found in studies analysing the differences in sex-specific deception that, when the opportunity to lie arises as a surprise, men are more likely to lie.4 They also stated that the opportunity to pre-plan did not affect male lying behaviour but increased the proportion of women lying. Surprisingly, however, if men were not allowed to lie in a first trial but were later permitted to do so, pre-planning increased their lying behaviour. Furthermore, if pre-planning was not possible, “then the opportunity to tell lies in the first stage increases lies in the second stage only for males”.4 No difference in men and women was seen when there was a possibility for pre-planning in general.4

Physiologically, many previous studies have concluded that the frontal cortex is key to lying, as it facilitates planning, attention and self-control. Similarly, an increase in prefrontal white matter is now known to be indicative of pathological liars.6 General behavioural studies have demonstrated that the left and right anterior prefrontal cortices (aPFCs) are engaged in deceptive behaviours, although the right aPFC was more involved in well-rehearsed lies than the left. In contrast, the anterior cingulate cortex (ACC) is more active during spontaneous, non-coherent, non-memorized lies.7

In conclusion, there are two main reasons for lying: there is more to gain from lying than there is to lose from telling the truth; or the individual is unable to discern what the truth is. Lying predominately activates the prefrontal cortex and, overall, studies have found that men tend to lie more than females. It was also found that the effect of pre-planning influences these statistics, both within and between sexes. When pre-planning is not possible, males tell more lies than females at the first opportunity, though females tell more lies initially if they know there will be future opportunities to do so. Further social and neurophysiological experiments may build on these discoveries, potentially benefitting work in the psychology and psychiatry sectors.


  1. Cambridge Dictionary. LIE | meaning in the Cambridge English Dictionary [Internet]. 2019. Available from:
  2. Mares AC, Turvey BE. The Psychology of Lying. False Allegations [Internet]. 2018;21–36. Available from:
  3. DePaulo BM, Kashy, DA, Kirkendol SE, Wyer MM, & Epstein JA. Lying in everyday life. Journal of Personality and Social Psychology, 70(5), 979–995. Available from:
  4. Chowdhury SM, Jeon JY, Kim C, Kim S-H. Gender Differences in Repeated Dishonest Behavior: Experimental Evidence. Games. 2021 May 21;12(2):44.
  5. Jung S, Vranceanu R. Experimental Evidence on Gender Differences in Lying Behaviour. Revue economique [Internet]. 2017;68(5). Available from:
  6. Grant JE, Paglia HA, Chamberlain SR. The Phenomenology of Lying in Young Adults and Relationships with Personality and Cognition. Psychiatric Quarterly. 2019 Jan 29;90(2):361–9.
  7. Karim AA, Schneider M, Lotze M, Veit R, Sauseng P, Braun C, et al. The Truth about Lying: Inhibition of the Anterior Prefrontal Cortex Improves Deceptive Behavior. Cerebral Cortex [Internet]. 2009 May 14;20(1):205–13. Available from:

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