Detecting lies has become somewhat of a big deal to our society. Multiple systems have been developed to accomplish such a feat, but how reliable are these methods? Research tells us that there hasn't yet been a breakthrough that allows us to be completely successful, although some theorists have much faith in their own process.
Paul Ekman, a psychologist, wrote the book Telling Lies in 1985 that later was the basis of the Fox TV series Lie to Me. In this book, Ekman writes about his theory of micro-expressions as revealers of emotion. He believes that when people try to hide their emotions a very quick facial expression emerges. This video shows an example of Ekman explaining his theory through a real world trial.
It seems like Ekman's approach works, but research argues that verbal cues are more reliable that non-verbal cues (which is what Ekman uses) in detecting lies. If you'd enjoy delving deeper into Ekman's work, feel free to visit his website.
The Polygraph Test
A more well-known approach is the polygraph test or the "lie-detector". This test assumes that the Pinocchio Response is real which means people have a supposedly perfect physiological or behavioral indicator of lying. In other words, a person's body will react much like Pinocchio's nose reacted when telling a lie, but in a more realistic way.
This test, however, has its problems. It confuses arousal with evidence of guilt. For example, Sally is being tested because she has been accused of stealing a necklace. Naturally, Sally is anxious even though she is innocent. This anxiety or arousal could easily mislead the test to report Sally as being a liar, and hence guilty.
After watching Ekman's video, how do you feel about his approach? Do you think it's unreliable?
Although several methods have been developed, why do you think detecting a lie is so difficult?