The speech-like sounds, which resemble a chorus of Martians, closely mimic the melodic aspects of speech. They also contain a fundamental frequency ?the core pitch of a voice, such as baritone or soprano, that helps us clue in to the identity of a voice. These non-speech stimuli were developed by Drs. Sonya Bird and Guy Carden in the Department of Linguistics and Dr. Janet Werker in the Department of Psychology, all at the University of British Columbia, where Dr. Vouloumanos was a doctoral student at the time of research.
In the first stage of the experiments, Dr. Vouloumanos and her colleagues compared the response of 10 to 72-hour-old infants to the speech-like sounds and those of monosyllabic nonsense words, such as "lif". When the neonate sucked on a sterilized pacifier, one or the other sound type was played for a one minute interval. The infants were observed for changes in their sucking behaviour.
"The neonates changed their behaviour to elicit speech," says Dr. Vouloumanos. "What we found is that their sucking behaviour increased to hear speech and it decreased when the sucking would elicit the non-speech sounds."
The study involved 20 neonates at British Columbia's Women's and Children's Hospital. The research, presently in press in the journal Development Science, revealed that the neonates sucked about 15-per cent more in response to the human speech compared with the analogue.
Having demonstrated that newborns could distinguish between these two types of very similar sounds, Dr. Vouloumanos then tested the core question: Had the infants already picked-up an ear for speech in the womb? Could the newborns discriminate between just the low frequency aspects (those that are heard across the womb) of th
Source:Natural Sciences and Engineering Research Council