Lie Motives

Dr. Lightman tells the bookstore audience he can spot a lie but isn’t able to know what motivated the lie. I have described eight different motives for lying. The most common one is to avoid being punished for breaking a rule, law, etc. The second most frequent motive for lying is to get something more easily or not otherwise obtainable without lying.

My newsletter “Reading Between The Lies,” describes the other six motives in newsletter #1.

Sign of Contempt

Right after Zoe says to Cal “it will take time” she shows a beautiful contempt expression, tightening one lip corner. It’s brief but slower than a micro. John Gottman’s research on marriage found that contempt is a serious indicator of trouble ahead: Zoe and Cal are divorced.

Multiple Personalities

Loker heralds what is going to come next by crediting handwriting as a reflection of personality – very few scientists who have studied the issue do. A few seconds later Lightman says Trisha has Multiple Personality Disorder. Foster corrects him substituting the more recent label: Dissociative Identity Disorder. She notes that the existence of such a disorder is just barely more plausible than psychic phenomena. While Loker calls it the Holy Grail of psychiatry, there actually is strong disagreement among mental health professionals about whether it is a legitimate diagnosis of a mental disorder which really occurs rather than a suggestible patient’s creation based on media depictions or a therapist’s belief in it. But it sets the stage for an entertaining story and some great acting.

Heart Rate

Measuring heart rate and blood pressure has the look of science, but does not usually reveal more than what Loker notes — overall level of emotional arousal. That is also evident in her face, which also usually shows which emotions are being aroused. Blood pressure, heart rate and skin conductance are the traditional measures in what is mistakenly called the ‘polygraph lie detector.’

For a critical evaluation of the polygraph see chapter 7 in my book Telling Lies; for a report focusing on its use in national security read The Polygraph and Lie Detection (on which I was one of the authors) free here, or on the National Academy of Sciences website.

Fear in the Eyes

Torres says she sees fear in the judge’s eyes, but the frozen video frame is inconclusive. There has to be a lot of white (sclera) exposed above the iris to be certain it is fear.

Pupil Dilation

Pupil dilation is a sign of sexual arousal, and also the arousal of fear, anger, or excitement.