"It's well established that neonates have a preference for speech above other sounds, but where does this come from? Is it something that's built in and there's something about the speech signal that they're tuned to listen to without the benefit of experience, or does it come from their prenatal experience in the womb? I think we've shown that there's an experience-independent component to newborns' preference for speech," says Dr. Vouloumanos, an Assistant Professor in McGill's Department of Psychology in Montreal, Canada.
She'll be presenting the findings of her latest research at the annual meeting of the American Association for the Advancement of Science in St. Louis, February 17th.
Neural and cochlear development is such that at about six months gestation the fetus begin to hear a range of frequencies. Thus, there's the possibility that newborns preferentially listen to speech because they're used to it from their in-utero tuning-in.
But, which speech sounds actually get through the uterine sound barrier to the fetus? According to Dr. Vouloumanos, the best evidence indicates that the uterine environment acts as a low-pass filter. This means that only very low, deep sounds those below about 400 Hertz make it to a fetus' ear.
Dr. Vouloumanos and colleagues developed a painstaking two part experimental procedure to separate out possible in-utero exposure from innate predisposition.