How the dilation of pupil identifies the liar?
Answers
In a small study of 32 people, researchers asked half of the participants to remember three facts about a false identity: a new name, date of birth, and hometown. Researchers then asked volunteers to answer the question "Is this true of you?" for different facts and to press a "yes" or "no" button in response. The people with a false identity were asked to practice lying by selecting "yes" for the new facts. Researchers measured response time and accuracy and, after 270 trials, or 20 minutes of practice, the liars’ values matched those of the truth-tellers.
Why does it take training to become skilled at telling a lie? Because lying requires some mental juggling, says Xiaoqing Hu, a study co-author and psychology doctoral candidate at Northwestern University. When you tell a lie, you have to hold two conflicting answers in mind and suppress the one that’s true. However, 20 minutes is enough time to memorize the lie completely, which means no extra thought is needed to tell it. Plus, psychologically, it’s possible that after repeating something to yourself over and over again, you can subconsciously convince yourself that it’s true, even when you (logically) know it isn’t