For face recognition to develop normally, infants need to be exposed to faces. Maurer and colleagues have studied the effects of early visual deprivation as a result of bilateral dense cataracts during infancy (Maurer et al., 2005 and Maurer et al., 2007). When infants are

born with this condition, their retinas do not receive patterned visual input for as long as the opaque lenses in their eyes have not been removed or replaced. Even when infants are treated within a few months after Selleck BIBF-1120 birth, some aspects of face recognition abilities fail to develop in later childhood (Le Grand, Mondloch, Maurer, & Brent, 2003; see Maurer et al. (2005), for a review). Whereas individuals, years after having been treated for early cataract, are able to distinguish faces normally on the basis of the external face contour or the forms of the facial features (mouth, nose, eyes), they have difficulty binding together facial features into a holistic gestalt (Le Grand, Mondloch, Maurer, & Brent, 2004) and to take into account the distance relations between the Ceritinib datasheet face features (Le Grand et al., 2001 and Le Grand et al., 2004). These abilities depend usually on right-hemisphere processing. Because they do not as a rule develop within the first few months of life when visual deprivation usually occurs, this indicates that early face exposure is important

in that it sets up the basic neural architecture in the right-hemisphere for later development of these abilities (cf. Maurer et al., 2007). Although early face input thus appears to be an important prerequisite for proper face recognition development, it is not known yet whether variations in type or quality of face exposure matter. Of course, variation in face exposure should not, for ethical reasons, be manipulated experimentally, but there are regularly occurring circumstances that may influence

the type of face exposure received by some infants. Most people prefer holding an infant to the left side of their body (see for a review, Donnot & Vauclair, 2005), presumably because of their own right-hemisphere lateralisation for face perception and because it 2-hydroxyphytanoyl-CoA lyase allows them to better monitor the infant’s own facial and other emotional expressions (e.g. Bourne and Todd, 2004, Harris et al., 2001 and Vauclair and Donnot, 2005; but see Donnot & Vauclair, 2007). For example, in a study with 287 mother–infant dyads, Salk (1960) found 83% of the right-handed and even 78% of the left-handed mothers to have a left-holding preference. According to Harris, 2010 and Harris et al., 2001 the left-side bias occurs on a test of imagination, as well as with real infants or with dolls and is mostly subconscious. The left-side bias cannot be explained by the heartbeat explanation, the favoured holding position, handedness or femaleness.