FRIDAY, Aug. 24, 2007 (HealthDay News) -- When interacting with their infants, female rhesus monkeys use special vocalizations similar to the "baby talk" used by human mothers to get an infant's attention, University of Chicago researchers report.
"Motherese is a high pitched and musical form of speech, which may be biological in origin," Dario Maestripieri, associate professor in comparative human development, explained in a prepared statement.
"The acoustic structure of particular monkey vocalizations, called girneys, may be adaptively designed to attract young infants and engage their attention, similar to how the acoustic structure of motherese, or baby talk, allows adults to visually or socially engage with infants," he said.
The researchers studied vocalizations among adult female rhesus macaques on an island off the coast of Puerto Rico. When a baby was present, there was a significant increase in the amount of grunts and girneys among the adult females.
"The calls appear to be used to elicit infants' attention and encourage their behavior. They also have the effect of increasing social tolerance in the mother and facilitating the interactions between females with babies in general. Thus, the attraction to other females' infants results in a relatively relaxed context of interaction where the main focus of attention is the baby," the researchers wrote.
The study was published in the current issue of the journal Ethology.
The American Speech-Language-Hearing Association outlines human speech and language development.