Lie to Me's main character, Dr. Cal Lightman, is based on Dr. Paul Ekman, a notable psychologist and expert on body language and facial expressions at University of California, San Francisco.
Ekman (born February 15, 1934) has been a pioneer in the study of emotions and their relation to facial expressions. He is considered one of the 100 most eminent psychologists of the twentieth century.
The background of Ekman's research analyzes the development of human traits and states over time. He emphasizes that the neuro-facial expressions used as the basis of his findings are cross-cultural and transcend our personal upbringing and influence of locale.
Currently, he is the Manager of The Paul Ekman Group, LLC (PEG), "a small company that produces training devices relevant to emotional skills, and is initiating new research relevant to national security and law enforcement."