In the Eye of the Holder

Faces are so special to humans that just three dots arranged as a face can change behaviour - an effect already present in childhood. Children held a plain sack randomly in either arm, but adding a ‘three-dot-face’ resulted in a preference to hold in the left arm, mirroring the left-cradling bias shown by mothers holding babies. Left-cradling places the baby’s face in the mother’s left visual field (LVF). The LVF is directly connected to the brain’s right hemisphere, which is specialised for processing social-emotional information. Studies show this effect is not related to handedness. A left bias was also seen when children held a human ‘baby’ doll but, interestingly, not an ‘orangutan’ doll. Children who held the ‘baby’ doll in their left arm scored higher on social ability tests, compared with right holders, indicating that the left-cradling bias is an evolutionarily old trait supporting infant wellbeing and social development.