An important component of the visual system is the ability to detect low contrasts items. When levels of contrast determinations are made, interventions can be developed, in this case, for infants, to develop better visual acuity. Expressions of faces and mediated by faint shadows and changes of the contours of the eye and mouth. Facial expressions are mostly in the low contrast, so an infant's reaction offers useful information when facial expressions react. Set of four cards measuring 9" x 9".