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.

‘Something in the way you move’: Infants are sensitive to emotions conveyed in action kinematics

“…Twenty‐three additional infants were tested but not included in the final analysis due to fussiness ( n = 11), not accepting electrodes on their face ( n = 7), or excessive movement artefacts in the signal ( n = 5). This high dropout rate is typical in EMG studies with infant and children population (Geangu et al, ; Isomura & Nakano, ). Parents were informed about the procedure and gave their written consent to their child's participation.…”

“…Another possible limitation is the attrition rate (60% of the sample), which could question the appropriateness of our paradigm for the population tested. However, high attrition rates are common in studies with infants and children that make use of sensors to measure electromyographic (Geangu et al, ; Isomura & Nakano, ) as well as electroencephalographic responses (Stets, Stahl, & Reid, ). In our study, almost 30% of the participants were excluded due to infants not accepting the sensors on their face and to movements artefacts.…”

“…Only very recently, facial EMG has started to be used as a tool to explore emotion processing in infancy (Datyner, Henry, & Richmond, ; Isomura & Nakano, ; Kaiser, Crespo‐Llado, Turati, & Geangu, ). These findings have shown that from 7 months on, infants respond with matching facial responses to happy and fearful faces, but not to angry faces (Datyner et al, ; Kaiser et al, ).…”

“…These findings have shown that from 7 months on, infants respond with matching facial responses to happy and fearful faces, but not to angry faces (Datyner et al, ; Kaiser et al, ). Moreover, 5‐month‐old infants showed selective facial activity in response to bimodal, but not unimodal, laughing and crying emotional expressions (Isomura & Nakano, ). In sum, these EMG studies are in line with behavioural and neuroimaging evidence showing that emotional processing abilities undergo significant development in the first year of life (Grossmann, Striano, & Friederici, ; Hoehl, ).…”

Expanding Simulation Models of Emotional Understanding: The Case for Different Modalities, Body-State Simulation Prominence, and Developmental Trajectories

“…Datyner et al (2017) showed similar results in 7-montholds viewing happy and angry facial expressions. Interestingly, Isomura and Nakano (2016) showed that infants aged 4-5 months showed increased corrugator EMG response to audiovisual crying and increased zygomaticus EMG response to audiovisual laughing, but no clear increase in response to unimodal emotional stimuli (faces or vocalizations individually). There is evidence that at this age, infants can discriminate happy, sad and angry emotions from bimodal audio-visual stimuli, but that sensitivity to unimodal auditory stimuli emerges at 5 months, and visual stimuli at 7 months (Flom and Bahrick, 2007).…”