Development of Effective Connectivity during Own- and Other-Race Face Processing: A Granger Causality Analysis.

Guifei Zhou,Xiao Pan Ding,Jiangang Liu,Genyue Fu,Kang Lee

doi:10.3389/fnhum.2016.00474

Abstract

Numerous developmental studies have suggested that other-race effect (ORE) in face recognition emerges as early as in infancy and develops steadily throughout childhood. However, there is very limited research on the neural mechanisms underlying this developmental ORE. The present study used Granger causality analysis (GCA) to examine the development of children's cortical networks in processing own- and other-race faces. Children were between 3 and 13 years. An old-new paradigm was used to assess their own- and other-race face recognition with ETG-4000 (Hitachi Medical Co., Japan) acquiring functional near infrared spectroscopy (fNIRS) data. After preprocessing, for each participant and under each face condition, we obtained the causal map by calculating the weights of causal relations between the time courses of [oxy-Hb] of each pair of channels using GCA. To investigate further the differential causal connectivity for own-race faces and other-race faces at the group level, a repeated measure analysis of variance (ANOVA) was performed on the GCA weights for each pair of channels with the face race task (own-race face vs. other-race face) as the within-subject variable and the age as a between-subject factor (continuous variable). We found an age-related increase in functional connectivity, paralleling a similar age-related improvement in behavioral face processing ability. More importantly, we found that the significant differences in neural functional connectivity between the recognition of own-race faces and that of other-race faces were modulated by age. Thus, like the behavioral ORE, the neural ORE emerges early and undergoes a protracted developmental course.

Highlights

IntroductionChildren typically have asymmetrical exposures to own- and other-race faces
From early childhood, children typically have asymmetrical exposures to own- and other-race faces
To obtain own-race face Granger causal networks, the effective connectivities were calculated with different intensities and directions among the 46 channels while children were recognizing the own-race faces

Summary

Introduction

Children typically have asymmetrical exposures to own- and other-race faces. One of the consequences of this early asymmetrical face exposure is that we recognize own-race faces faster and more accurately than other-race faces. This phenomenon is referred to as the other-race effect (ORE; for reviews, see Meissner and Brigham, 2001; Sporer, 2001; Anzures et al, 2013a). Numerous developmental studies have revealed that ORE emerges as early as in infancy (Sangrigoli and de Schonen, 2004; Hayden et al, 2007; Kelly et al, 2009) and develops steadily throughout childhood (Chance et al, 1982; Pezdek et al, 2003; Walker and Hewstone, 2006; Goodman et al, 2007; Anzures et al, 2014)

Methods

Results

Discussion

Conclusion