Neural Discrimination of Facial Cues Associated With Trustworthiness in Adults and 6-Month-Old Infants as Revealed by Fast Periodic Visual Stimulation

• Published in: Developmental psychology 2023-11, Vol.59 (11), p.2080-2093
• Main Authors: Baccolo, Elisa, Peykarjou, Stefanie, Quadrelli, Ermanno, Conte, Stefania, Macchi Cassia, Viola
• Format: Article
• Language: English
• Subjects: Adults; Age Differences; Brain Hemisphere Functions; College Students; Credibility; Cues; Discrimination; Electroencephalography; Face; Face Perception; Facial expressions; Feedback (Response); Female; Human; Infants; Interpersonal Competence; Localization; Male; Nonverbal Communication; Responses; Sequences; Stimulation; Stimulus; Trust (Psychology); Trust (Social Behavior); Visual Discrimination; Visual Stimulation; Visual Stimuli; Young adults; Young Children
• ISSN: 0012-1649; 1939-0599
• DOI: 10.1037/dev0001594

Adults and children easily distinguish between fine-grained variations in trustworthiness intensity based on facial appearance, but the developmental origins of this fundamental social skill are still debated. Using a fast periodic visual stimulation (FPVS) oddball paradigm coupled with electroencephalographic (EEG) recording, we investigated neural discrimination of morphed faces that adults perceive as low- and high-trustworthy in a sample of 6-month-old infants (N = 29; 56% male; Mage = 196.8 days; all White) and young adults (N = 21; 40% male; Mage = 24.61 years; all White) recruited in Italy. Stimulus sequences were presented at 6 Hz with deviant faces interleaved every fifth stimulus (i.e., 1.2 Hz); oddball category (high/low trustworthiness) was varied within subjects. FPVS responses were analyzed at both frequencies of interest and their harmonics as a function of deviant type (high- vs. low-trustworthy) over occipital and occipitolateral electrode clusters. For both infants and adults, the baseline response did not differ between trustworthiness conditions. Significant responses were centered on the right parietal electrodes in infants, and on the occipital and left occipitotemporal clusters in adults. Oddball responses were significant for both infants and adults, with cross-age differences in the topographical localization of the response on the scalp. Overall, results suggest that, by the age of 6 months, infants discriminate between faces that adults rate as high and low in trustworthiness, extending prior evidence of early sensitivity to this face dimension in humans. Public Significance StatementThe current study provides novel evidence that the human brain discriminates between faces that adults rate as high or low in trustworthiness, suggesting that sensitive responding to facial cues associated with trustworthiness is an early emerging and foundational feature of human social competences. Additionally, it demonstrates that the fast periodic visual stimulation paradigm is an effective tool for elucidating the ontogenetic roots of this sensitivity in early infancy.