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Key points
- Effective lying involves knowing what the receiver of the lie knows.
- Studies suggest that liars do take into account the receiver's knowledge.
- Liars are also sensitive to the costs of being caught.
- Liars tend to exploit mistaken beliefs of receivers to gain an advantage.
The general concept of lying is one we’re all familiar with. The liar deliberately says something to a receiver that is intended to lead the receiver to believe something the liar knows is not true. Hidden within this fairly simple definition, though, is the recognition that lying successfully is likely to require a fair amount of thought.
The type of thinking that lying requires was explored in a 2023 paper by Lauren Oey, Adena Schachner, and Edward Vul, published in the Journal of Experimental Psychology: General.
The researchers start by exploring a few things people need to take into account in order to lie successfully. One thing liars have to do is determine the likelihood that they will get caught in a lie. They should be less inclined to lie in situations when they're likely to be caught than when they are not. In addition, liars should be aware of the potential punishments associated with being caught in a lie. Lying should be more common when the consequences are small than when they are large.
Two studies in this paper used a setting in which participants were given an opportunity to lie to a randomly assigned partner. In the first study, participants communicating via computer could see a box full of red and blue balls and understood that 10 balls would be drawn from the box at random. The participant was told they would receive a number of points based on the number of red balls drawn, while their partner would receive a number of points based on the number of blue balls drawn. Then, only the participant was shown the number of red and blue balls.
The participant had to tell their partner how many red balls were drawn, and the partner could either accept this report or challenge it as a lie. If the partner successfully challenged a lie, then the participant was penalized points. If the partner claimed that a truthful statement was a lie, then the partner was penalized.
Finally, on some trials, the box was 20 percent red balls and 80 percent blue; on some, the red and blue balls were split 50/50; and on some trials, the box was 80 percent red balls and 20 percent blue.
This setup creates an incentive for participants to lie in order to maximize the number of points they get. But there is a penalty for being caught in a lie.
The lies people told were related to the setup of the study in ways that make it clear the liars are paying attention to the knowledge of the receiver. Participants lied by using larger numbers of red balls when there was a higher proportion of red balls in the box than when there was a lower proportion. In addition, the more red balls that were actually drawn, the less likely participants were to lie (because there was no reason to lie when the situation was already good). Finally, the stronger the punishment for lying, the less likely a participant was to lie.
A second study added another clever wrinkle to the experimental design that clarified the findings of the first study. This second study varied what the participant and receiver were able to see. Participants were told that they could see everything in the box, while receivers could only see a subset. The participant knew both the true contents of the box as well as what the receiver believed to be in the box.
Like the first study, this experiment was set up so that there were actually 80 percent red balls on some trials, 50 percent on others, and 20 percent on others. Crucially, it was also constructed so that the receiver believed that there were 80 percent, 50 percent, and 20 percent red balls in a way that was independent of what was actually in the box. For example, there were some trials in which the receiver was led to believe that there were 20 percent red balls in the box when there were actually 80 percent.
In this version of the study, the liars generated their lies based only on what the receiver believed was true regardless of what was actually true. For example, if a box had only 20 percent red balls in reality, but the receiver believed that there were actually 80 percent red balls, then participants were quite likely to lie and say that many red balls were drawn (even though only a few were likely to have actually been drawn). So, participants calibrated their lies to the knowledge of the receiver, which demonstrates that liars are keeping the knowledge of the receiver in mind when constructing lies.
These studies demonstrate that lying is a complex activity that requires paying attention to the actual situation in the world, the beliefs of the person receiving the lie, and the potential dangers of being caught in a lie. This workload is one of the reasons why lying is stressful. When a situation has a number of facets to keep track of, lying is a complicated thing to do well. On top of that, in many real-world situations (unlike this experiment), a liar has to remember their lies in order to maintain consistency in what they say over time. That adds to the cognitive difficulty of lying successfully.
References
Oey, L. A., Schachner, A., & Vul, E. (2023). Designing and detecting lies by reasoning about other agents. Journal of Experimental Psychology: General, 152(2), 346–362. https://doi.org/10.1037/xge0001277
