Holding-side influences on infant's view of mother's face.

Recently we found that adult children whose mothers had had a right-arm preference for holding infants have a reduced left bias for recognising faces, suggesting that they are less well right-hemisphere lateralised for perceiving faces. One possible explanation of this finding is that early visual exposure to faces is suboptimal for right-held infants. To test this idea, we asked mothers to pick up a doll with an inbuilt camera in its face and to start bottle-feeding it. The results showed that less was visible of the face of mothers who held the doll on their right arm in comparison to those who held the doll on their left arm: From the right arm, the mother's left half of the face was less visible when the mothers were looking up and their right half of the face was less visible when they were looking at the doll. These results suggest that right-held infants receive suboptimal information from faces. Because early face exposure is important for face-processing development, the suboptimal face exposure probably experienced by right-held infants may have consequences for their ability to recognise faces and facial emotion later in life.