Neural Correlates of Infant Attention During Initial Exposure to Own- and Other-Race Faces

Past research has shown that infants raised in a racially homogenous environment demonstrate an advantage for processing own-race faces at the individual level in comparison to other-race faces (Lewkowicz, 2014; Mauer & Werker, 2014; Quinn, Lee, & Pascalis, 2018). This advantage for processing own-race faces develops across infancy and has been referred to as the own-race bias (e.g., Anzures, Quinn, Pascalis, Slater, Tanaka, & Lee, 2013). The processes that lead to development of the own-race bias are complex and not fully understood. Recent work suggests that by 10 months of age, differences in own- and other-race face processing may be related to attentional processes (Roth & Reynolds, 2022). The current study utilized event-related potentials (ERP) to examine neural correlates of infant attention during initial exposure to own- or other-race faces. Level of attentional engagement was also compared across early to late trials to determine whether infants demonstrated increased or decreased attention to a face with repeated exposure depending on race. Twenty-three infants were tested at 10 months of age. Only infants raised in a racially homogenous environment (based on parental report) were included in the dataset. Participants were familiarized with 20 repeated 1000 ms presentations of a single exemplar of either an own-race face (n = 13) or an other-race face (n = 10). Following familiarization, presentations of the familiar face were interspersed with presentations of novel faces until the infant was off task. EEG was recorded throughout testing using the EGI Geodesic EEG System (GES 400) 128-channel system with a 1000 Hz sampling rate. An offline bandpass filter was applied from 0.10 to 30.00 Hz. The analysis of the EEG focused on the Nc ERP component associated with level of attentional engagement in infancy (Reynolds & Richards, 2005). Mean amplitude of the Nc component was analyzed at midline-frontal electrodes from 345-650 ms following stimulus onset using a 200 ms prestimulus baseline period. Participants contributed a minimum of 8 artifact-free trials per condition to the ERP averages. Infants familiarized with an other-race face demonstrated greater amplitude Nc in comparison to infants familiarized with an own-race face (F(1,21) = 4.65, p = 0.037, ηp2 = .191). Interestingly, infants showed increased Nc amplitude to other-race faces following familiarization and decreased Nc amplitude to own-race faces following familiarization. These findings indicate that 10-month-old infants demonstrate greater attentional engagement during initial exposure to other-race faces than during initial exposure to own-race faces. This greater amplitude Nc could reflect a novelty effect for other-race faces for infants raised in racially homogenous environments. The increase in Nc amplitude following familiarization with an other-race face may be indicative of continued attentional engagement due to incomplete processing of the face. Given the potential for early developing perceptual biases to contribute to subsequent development of social biases and prejudice (Xiao et al., 2018, 2019), these findings provide important insight into potential mechanisms associated with the own-race bias in face processing in infancy.