It might be easier to lie in a foreign language. A little background first: according to the cognitive load hypothesis, lying should be harder in a foreign language because both lying and speaking in a foreign language make your brain work harder.
But according to the emotional distance hypothesis, lying should be easier in a foreign language because speaking in a foreign language is less emotionally arousing than speaking in your native tongue, so the stress you feel while lying gets dampened.
To see which hypothesis won out, psychologists had participants lie or tell the truth while answering questions. They found that participants generally took longer to lie than to tell the truth, but that the time difference shrank when the participant was speaking in a foreign language.
But that's because it took participants longer to tell the truth in a foreign language--not because participants could lie faster. The researchers think they can explain their results using both hypotheses: people took longer to tell the truth in a foreign language because the extra cognitive load of speaking a different language made it harder.
Lying should have taken even longer because it makes the brain work even harder, but the emotional distance that speaking in a foreign language creates canceled out some or all of that extra cognitive load.
- Suchotzki, K., & Gamer, M. (2018). The language of lies: Behavioral and autonomic costs of lying in a native compared to a foreign language. Journal of Experimental Psychology: General. 147 (5), 734-746.