Ana Maria Vaz Portugal Da Silva: "The genetic specificity of infant social attention"

Ana Maria Vaz Portugal Da Silva, Karolinska Institutet: "The genetic specificity of infant social attention: the case of orienting versus sustained looking to faces”

Abstract
Looking at faces, the hallmark of social attention, is present at birth and is thought to be atypical in heritable neurodevelopmental conditions such as autism. According to one theory, face looking draws on two distinct neural processes: a subcortical one that promotes initial and fast orienting to faces appearing in the periphery, and a cortical route linked to top-down and sustained attention to the attended face (Johnson, Senju, and Tomalski, 2015). So far, no study (at any age) has probed whether face looking, when in competition with other objects, is a heritable phenotype, or whether orienting to faces versus sustained looking at faces have shared or distinct genetic etiologies. In a study of 536 5-month-old twins, we show that face looking is heritable, both face preference (the maintenance of attention to the face as the preferred target of attention, h2 = .46) and face capture (the orienting to the face as the first target of attention, albeit to a smaller degree, h2 = .19). Face capture was not associated with later developmental outcomes, but higher face preference was associated with higher parental ratings of verbal competence in toddlerhood. The phenotypic association between face capture and face preference (rPh = .30) was mostly explained by shared genetic factors. Further, we found tentative evidence of unique genetic factors associated with face preference beyond those shared with face capture. This study provides both developmental and etiological evidence supporting the hypothesis that face orienting is partly dissociable from face preference in early infancy, hence contributing to a new understanding of the heterogeneous nature of social attention.