It is well known from birth that faces are salient, preferred over other stimuli, and are readily discriminated. It has also been shown that over the course of development infants’ proclivity for face discrimination is influenced by their social environment. Pascalis, deHann, andNelson (2002), for example, demonstrate that 6-month-olds are able to discriminate various monkey faces as well as human faces whereas 9-month-olds can only discriminate different human faces. Importantly, however, if 6-month-olds receive 1-2 minutes per day of familiarization with photographs of monkey faces three months later the now 9-month-olds can still discriminate unfamiliar and familiar monkey faces. Like face perception, infants’ discrimination of speech also varies as a function of experience and exposure. Four-to 6-month-olds discriminate speech sounds in their native and non-native languages; however, by10-to12-months of age infants can only discriminate speech sounds common to their native language.