title: Automatic facial mimicry in response to dynamic emotional stimuli in five-month-old infants.
abstract: Human adults automatically mimic others' emotional expressions, which is believed to contribute to sharing emotions with others. Although this behaviour appears fundamental to social reciprocity, little is known about its developmental process. Therefore, we examined whether infants show automatic facial mimicry in response to others' emotional expressions. Facial electromyographic activity over the corrugator supercilii (brow) and zygomaticus major (cheek) of four- to five-month-old infants was measured while they viewed dynamic clips presenting audiovisual, visual and auditory emotions. The audiovisual bimodal emotion stimuli were a display of a laughing/crying facial expression with an emotionally congruent vocalization, whereas the visual/auditory unimodal emotion stimuli displayed those emotional faces/vocalizations paired with a neutral vocalization/face, respectively. Increased activation of the corrugator supercilii muscle in response to audiovisual cries and the zygomaticus major in response to audiovisual laughter were observed between 500 and 1000 ms after stimulus onset, which clearly suggests rapid facial mimicry. By contrast, both visual and auditory unimodal emotion stimuli did not activate the infants' corresponding muscles. These results revealed that automatic facial mimicry is present as early as five months of age, when multimodal emotional information is present.
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan isomurat8818@gmail.com.
authors.forename: Tomoko
authors.identifier: 0000-0003-1230-3597
authors.initials: T
authors.lastname: Isomura
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.|Department of Brain Physiology, Osaka University School of Medicine, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Tamami
authors.identifier: 0000-0002-6955-1164
authors.initials: T
authors.lastname: Nakano
mesh_terms: D004576:Electromyography; D004644:Emotions; D005145:Face; D005149:Facial Expression; D005152:Facial Muscles / Q000502:physiology; D006801:Humans; D007100:Imitative Behavior; D007223:Infant
keywords: EMG; emotion; facial mimicry; infants