Experiments have shown that infants listen longer to songs when they are sung in a higher pitch (Trainor and Zacharias 1998). And high-pitched vocalizations are used as attention-getters among a variety of species. For example, macaques use high-pitched calls to get the attention of other group members (Koda and Masataka 2003).
There is also evidence that human mothers modulate their pitch according to their babies’ levels of attentiveness. In a Japanese study, mothers spoke with lower-pitched voices when their babies were vocally responsive (Niwano and Sugai 2003). But when babies were more reticent, moms raised the pitch.
In a 2015 study by McGill University, Canadian researchers discovered that 6-month-old infants were much more attracted to their own speech patterns than those of adults. The infants listened to “a repeating vowel sound that mimicked those made by an adult woman or those by a baby” using a synthesis tool. Researchers measured the length of each infant’s attention span. On average, the infants listened to a fellow baby’s vowels 40 percent longer than the adult woman’s vowels. It’s important to note that the “infant-like vowel sounds that they heard were not yet part of their everyday listening experience.” Meaning, the babies weren’t partial to their own kind simply out of familiarity. Knowing infants’ speech preferences can help us design more effective tools in developing their speech.
Sources: parenting science,curiosity