title: My Brain Reads Pain in Your Face, Before Knowing Your Gender.
abstract: Humans are expert at recognizing facial features whether they are variable (emotions) or unchangeable (gender). Because of its huge communicative value, pain might be detected faster in faces than unchangeable features. Based on this assumption, we aimed to find a presentation time that enables subliminal discrimination of pain facial expression without permitting gender discrimination. For 80 individuals, we compared the time needed (50, 100, 150, or 200 milliseconds) to discriminate masked static pain faces among anger and neutral faces with the time needed to discriminate male from female faces. Whether these discriminations were associated with conscious reportability was tested with confidence measures on 40 other individuals. The results showed that, at 100 milliseconds, 75% of participants discriminated pain above chance level, whereas only 20% of participants discriminated the gender. Moreover, this pain discrimination appeared to be subliminal. This priority of pain over gender might exist because, even if pain faces are complex stimuli encoding both the sensory and the affective component of pain, they signal a danger. This supports the evolution theory relating to the necessity of quickly reading aversive emotions to ensure survival but might also be at the basis of altruistic behavior such as help and compassion.
  
  
  CONCLUSIONS
  This study shows that pain facial expression can be processed subliminally after brief presentation times, which might be helpful for critical emergency situations in clinical settings.
authors.affiliation: Neurosciences Research Center of Lyon, INSERM U 1028, Lyon, France; University Claude Bernard Lyon 1, Lyon, France. Electronic address: claire.czekala@gmail.com.
authors.forename: Claire
authors.initials: C
authors.lastname: Czekala
authors.affiliation: Neurosciences Research Center of Lyon, INSERM U 1028, Lyon, France; University Claude Bernard Lyon 1, Lyon, France; Functional Neurology and Epilepsy Department, Hospital Center Pierre Wertheimer, Lyon, France.
authors.forename: François
authors.initials: F
authors.lastname: Mauguière
authors.affiliation: EMC Laboratory University Lumière Lyon 2, Lyon, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Mazza
authors.affiliation: Ecole de Psychologie, Laval University, Quebec, Canada.
authors.forename: Philip L
authors.initials: PL
authors.lastname: Jackson
authors.affiliation: Neurosciences Research Center of Lyon, INSERM U 1028, Lyon, France; University Claude Bernard Lyon 1, Lyon, France.
authors.forename: Maud
authors.initials: M
authors.lastname: Frot
mesh_terms: D000293:Adolescent; D000328:Adult; D000533:Altruism; D004644:Emotions; D005149:Facial Expression; D000066499:Facial Recognition; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000523:psychology*; D012737:Sex Factors; D017603:Signal Detection, Psychological; D013360:Subliminal Stimulation; D013997:Time Factors; D055815:Young Adult
keywords: Masked facial features; area under the receiver operating characteristic curve; pain facial expression; reportability; sensitivity