Darwin, Charles

Charles Darwin left the world a substantial legacy of theory and research through both animal and human observational and experimental study. An English naturalist, Darwin proposed in his book On the Origin of Species (1859) the theory of evolution of species by descent from common ancestors, describing the evolutionary mechanism of natural selection and the struggle for survival. Darwin's works have informed and at times predicted future research on deception in the social and evolutionary sciences. While Darwin did not often directly write on deception, and while such descriptions often focused more on animals than humans, Darwin's ideas are a forerunner of modern deception research regarding both detection and practice.

Darwin mentions human deception detection in his book The Expression of the Emotions in Man and Animals (1872), in which he argues that facial expressions are inherited and adaptive for the persons generating an emotion, allowing for better reaction to their environmental context. Darwin describes communication with colleagues who [Page 243]report how people of various races detect deceit from expressions. Shifty and guilty eyes and eye movements play a prominent role in these descriptions, which foreshadow later work on beliefs about deception detection. Darwin did not focus on the mechanics of differentiating deceptive from genuine emotionally rich facial expressions or on their production, but his ideas concerning betrayal of true feelings and of feigned emotional expressions led him to originate two important hypotheses in early deception-detection research. Paul Ekman refers to the first as the inhibition hypothesis: If one cannot produce an action voluntarily, then one cannot prevent it when it is triggered by involuntary impulses such as emotion. The second involves Darwin's idea that facial muscles are the most difficult to control when one is emotional and that body cues (e.g., shaking from anger) are easier to suppress.

Ekman has argued that Darwin's first hypothesis is consistent with his own hypothesis concerning emotional leakage (betrayal of emotion, despite attempted concealment). Similarly, Ekman and his colleagues' work on microexpressions (brief, involuntary facial expressions presumably caused by emotional experience) directly follow on Darwin's idea regarding leakage. Darwin also refers to what is now called the Duchenne smile—the genuine smile, almost impossible to voluntarily produce or prevent.