Can you tell when someone is lying to you?

As any fan of the television show Sherlock knows, part of the fun is watching a protagonist who can spot a liar a mile away. That's because, despite what we tell ourselves, we're actually pretty easily duped.

According to a new study from the University of British Columbia, it may be our smugness that's blinding us to deception: The people who think they should be the best at catching a lie are actually the worst.

In the study, published in the journal Legal and Criminological Psychology, researchers gave the 116 participants a standard questionnaire on emotional intelligence, a measurement of a person's ability to assess and manage emotions in themselves and other people.

Then they were shown 20 videos of people pleading for the safe return of kidnapped family members. (Half of the time, the person making the plea had been found to be responsible for the missing loved one's disappearance.) Researchers asked the participants to evaluate whether the pleas were honest, their confidence in their assessment, and what they based it on.

The participants who scored the highest on EQ scale – those who demonstrated better skills when it came to perceiving emotions – were the most likely to have assume the liars were being honest.

Stephen Porter, director for the Centre for the Advancement of Psychological Science and Law, told Science Daily that basically people became overconfident, and assumed truth where it didn't exist.

Part of lab's research explores how to better train police and other authorities to watch for liars in their facial movements and word use, by coding television footage of murderers making disingenuous pleas for help.

For instance, here's how not to be deceived: Liars speak more slowly, with more "ums" and "ahs," and often use few hand and arm movements. Deceptive murderers were more likely to express disgust than sadness, if only in brief facial expressions. They used more tentative language, as if suggesting that the victim "may" not be found, so they don't have to commit to the lie, while genuine family members are more likely to address the victim directly.

The best tip, however, may be not to assume you have someone all figured out.

Elementary, Dr. Watson.

Think you would know a lie when you hear one?