Joe Flynn & Tasha Hanley DARWIN THE DETECTIVE: OBSERVABLE FACIAL MUSCLE CONTRACTIONS REVEAL EMOTIONAL HIGH-STAKES LIES

ASSERTIONS MADE BY DARWIN Emotional expressions are: Inherited Involuntary Emotion-based Adaptive

DARWIN’S INHIBITION HYPOTHESIS Some “emotional” facial muscles can’t be inhibited Attempts to hide these will fail Previous studies support this

Some facial muscles are involuntary and will signal emotions Do you remember which part of the face the study hypothesized would be more associated with involuntary movement (lies)? Emotional leaking is likely to happen when the lie is complex and/or associated with strong emotions that have to be concealed People perform at chance levels when asked to gauge if someone is lying People lie (on average) 2x a day DECEPTION BRINKE ET AL GENERAL HYPOTHESIS

STUDY Looked at videotaped behaviors of 52 people emotionally asking for the return of a missing relative Half of these (n=26) people were later determined to be guilty of murdering the missing person (based on “overwhelming evidence”) Looked at muscle activation associated with surprise, sadness, and happiness Very specific coding system (Facial Action Coding System)

Hypothesis 1 & 2: Genuinely upset people will show more activation of the (1) corrugator supercilii and of the depressor anguli oris (2)

Hypothesis 3 &4: Deceivers will show activation of the frontalis- which pulls up the eyebrows (only the medial frontalis is relevant to sadness) and (4) produce more voluntary smiles (zygomatic major)

RESULTS Genuine pleas lasted longer “Honest” pleas did activate the corrugator supercilii for longer than the deceivers (H1) H2 was not statistically significant but seemed to be supported H3 was supported- liars activated the frontalis more H4 was also supported- deceivers DO smile more

Note: Relationship totals exceed sample size due to several cases of

DISCUSSION Deceptive people from the study: Activated specific facial muscles’ associated with lying Had more gross frontalis activation Smiled more frequently (thought to mask emotional leaks) Genuine pleaders from the study: Often showed activation of innate grief muscles (transcultural & Darwin said these displays facilitated human communication) Had contractions of the corrugator supercilii for a greater proportion of their pleas (Hypothesis 1) The depressor anguli oris was engaged more often (Hypothesis 2)

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