Research On The Developmental Mechanism Of Other-Race Effect Based On The Causal Functional Brain Network Analysis

As one of special phenomena in face recognition, the other-race effect (ORE) refers to a significantly better memory and recognition for own-race faces than other-race faces. The ORE interferes the inter-race social interaction, and even seems related to racial prejudice or racial stereotype. Therefore, the exploration of mechanism underlying ORE has been a hot research topic in the fields of psychology and cognitive neuroscience.Numerous developmental studies have suggested that the ORE emerges as early as in infancy and develops steadily throughout childhood until becoming robust in adulthood. However, there is very limited research on the neural mechanisms underlying this developmental ORE. Specifically, using the functional magnetic resonance imaging (fMRI) or the event-related potential (ERP), some existing researches had confirmed the significant differences in neural response or functional connectivity for own-and other-race face recognition in adult brain. In contrast, the neural research for children’s ORE was relatively few, not to mention the study aiming to reveal the developmental trajectory of neural ORE. Due to the lack of evidence regarding its development trajectory, the neural mechanism of the other-race effect remains unclear.Recently, functional near-infrared spectroscopy (fNIRS) as one of relatively new non-invasive functional neuroimaging techniques has been increasingly applied to the studies of brain function. Due to the evident advantages such as simple operation, high safety, low cost, wide application and high time resolution, fNIRS has been suggested to be more appropriately for children’s cognitive function research or experiments required relatively strong interaction. Thus, the present study use fNIRS to explore the development of own-and other-race face recognition in children, and reveal the development trajectory of NORE based on effective connectivity (EC) analysis. The main works are as follows:First, using the multi-channel functional near-infrared system, the present study detected the functional activities in the frontal and occipital cortical regions of Chinese children aged 3 to 13 years old when they recognized the Chinese faces and Caucasian faces. We used the "old-new" paradigm to assess the ability of children’s face recognition, and used the mixed experiments designed to explore the face race and age interaction for face processing.Second, the present study used Granger causality analysis (GCA) to examine the effective connectivity for each pair of channels.Third, at the group level, a repeated measures analysis of variance (ANOVA) was performed on the GCA weights for each pair of channels to explore the modulation of age for NORE. Further, the present combined with the linear correlation analysis and post hoc T-test to investigate the developmental model of NORE.Through these methods, the present find:First, the older children developed a more complex face recognition network than younger children, paralleling a similar age-related improvement in behavioral face processing ability.Second, the difference in causal network between own-and other-race face recognition (NORE) modulated by age. Namely, NORE was changing with increased age and underwent a protracted developmental course. We further found two different development models of NORE with age.Third, children were sensitive to method and experimental environment. Therefore, children’s behavioral other race effect was vulnerable and not robust like adults. This also showed that neural response was more sensitive than behavioral response.