One lie can easily turn into two, and small lies can easily become big lies. And today I encountered some recent research that suggests why.
Whenever you tell a lie, you experience a little twinge of emotion - usually guilt. That guilt may not be enough to keep you from lying, especially if the lie benefits you and does not necessarily hurt someone else. And past research has shown that increased exposure decreases our emotional response over time. So just like your first break-up is likely to hurt a lot more than your fifth break-up (cue "The First Cut is the Deepest"), the guilt you feel from your first lie is going to be much greater than the guilt you feel after lie #793.
To test this hypothesis, and get at the specific brain response to lies, researchers had people participate in a game while undergoing functional Magnetic Resonance Imaging (fMRI):
Specifically, we adapted a two-party task used previously to elicit and measure dishonesty. Participants advised a second participant, played by a confederate, about the amount of money in a glass jar filled with pennies. We changed the incentive structure over the course of two experiments such that dishonesty about the amount of money in the jar would either benefit the participant at the expense of their partner (Self-serving–Other-harming, Experiment 1), benefit both (Self-serving–Other-serving, Experiment 1), benefit the partner at the expense of the participant (Self-harming–Other-serving, Experiment 1), benefit the participant only without affecting the partner (Self-serving, Experiment 2) or benefit the partner only without affecting the participant (Other-serving, Experiment 2). Importantly, the participants believed that their partner was not aware of this incentive structure but thought that they were working together at all times to provide the most accurate estimate, which would benefit them both equally. A baseline condition enabled us to infer the amount of dishonesty on each trial without the participant being instructed to act dishonestly or required to admit to dishonesty.The researchers observed dishonesty escalation - that people became more dishonest over time - when it was self-serving. This was the case even when the lie hurt the other person, though people were more likely to be dishonest when served the other as well. (So they still lied if it hurt the other, but not as much as if it helped the other.) Results from the brain scan showed reduced amygdala activity over time. As I've blogged about previously, the amygdala, part of the mid-brain, is involved in emotional response.
So, to answer Liz Phair's question, "Why I Lie?" the answer is: it just keeps getting easier.