Processing of infant-directed speech by adults

Adults typically address infants in a special speech mode called infant-directed speech (IDS). IDS is characterized by a special prosody (i.e., higher pitched, slower and hyperarticulated) and a special lexicon ("baby talk"). Here we investigated which areas of the adult brain are involved in processing IDS, which aspects of IDS (prosodic or lexical) are processed, to what extent the experience of being a parent affects the way adults process IDS, and the effects of gender and personality on IDS processing. Using functional magnetic resonance imaging, we found that mothers with preverbal infants showed enhanced activation in the auditory dorsal pathway of the language areas, regardless of whether they listened to the prosodic or lexical component of IDS. We also found that extroverted mothers showed higher cortical activation in speech-related motor areas than did mothers with lower extroverted personality scores. Increased cortical activation levels were not found for fathers, non-parents, or mothers with older children.