Confirmed: It takes 20 seconds to spot a liar

Researchers recruited 24 couples and asked each person to talk about a time when he or she had suffered. Meanwhile, cameras recorded the reactions of the speaker’s partner. A separate group reviewed the videos, and was able to identify fake compassion in the reacting partners within 20 seconds.

After researchers took DNA samples of the study participants, it turned out that 60 percent of the least-trusted participants lacked a gene receptor, GG genotype, that may control your compassion and empathy. The receptor helps regulate your body’s level of oxytocin, which past studies have linked to feelings of trust, empathy, and generosity, explains Alexsandr Kogan, Ph.D., a post-doctoral fellow at the University of Toronto and the study’s lead author.