Babies may be incapable of talking, but at just a few months old, they've already developed many of the characteristics that will one day make their speaking voice distinct. That's the takeaway from a new study, reported by The New York Times, in which a team of bioacoustic researchers found that you can tell what infants will sound like at age 5 by analyzing their cries.
For their study, published in the journal Biology Letters [PDF], the researchers recorded the voices of 15 French children 4 to 5 years old. They then compared the clips to the children's "mild discomfort cries" recorded when they were 2 to 5 months old. The results showed that a baby's voice can be used to predict 41 percent of the variances they will have in their vocal pitch at age 5.
Other studies have suggested that what our voices sound like when we're young is a strong indicator of what they will sound like later on—even after puberty changes our vocal cords. A boy's voice pitch at age 7 can predict up to 64 percent of the distinguishing features his voice will have as an adult.
The study authors write that many of these variances may develop before childhood, and potentially in utero: "These observations suggest that inter-individual differences in [voice pitch] arise early in life and are largely unaffected by puberty, and raise the possibility that [pitch] may even be determined before birth."
The most important markers that determine pitch are the length, size, and tension of our vocal folds. But those aren't the only determinants: Environmental factors like smoking, pollution, and climate can affect how our voices sound as well, though these changes are usually temporary.
[h/t The New York Times]