Maternal accommodation in infant-directed speech during mother's and twin-infants' vocal interactions.

In this study a mother's instinctive accommodations of vocal fundamental frequency (f0) of infant-directed speech to two different infants was explored. Maternal speech directed to individual 3-mo.-old fraternal twin-infants was subjected to acoustic analysis.

Acoustic determinants eliciting Japanese infants' vocal response to maternal speech.

Generally, infants prefer infant-directed speech to adult-directed speech. This study investigated which acoustic features of maternal infant-directed speech elicit effectively 3-mo.-old infants' vocal response.

Object-related knowledge and the production of gestures with imagined objects by preschool children.

Previous research suggests that the gestural representation of preschool age children has a symbolic quality in the absence of real objects. It has shown a developmental progression from use of concrete body parts to more abstract imaginary-object gestural representations during the preschool years. The present study examined whether object-related knowledge is involved in the production of imaginary-object gestures.