Bortfeld's research, which appears in the upcoming April 2005 issue of Psychological Science, shows that babies use familiar words such as their names as a sort of "anchor" into the speech stream. A baby as young as six months can learn to recognize an individual word that follows its own name, even after hearing both words as part of whole sentences, says Bortfeld who worked with colleagues from Brown University and the University of Delaware.
"Recognition drives segmentation of the speech stream, and segmentation is a critical step in learning a language," Bortfeld explains. "We know from previous research that babies are recognizing their names in fluent speech by the age of six months, so we hypothesized that they should be able to use that recognition to segment the speech stream and recognize new words."
Much in the same way a person might have difficulty understanding a foreign language because it's hard to tell where one word starts and another begins, babies face a similar challenge in learning language. Bortfeld's research shows babies can begin to discern the beginnings and endings of words that follow their names, meaning their names form a foundation for learning language.
In what can be described as a "popping out" pattern, Bortfeld explains, one familiar word can allow a baby to pick out another word, and that newly familiar word may allow a baby to learn words that follow it.
Bortfeld and her colleagues tested babies by having them listen to sentences containing the pairing of one target word with the baby's own name such as "Emma's cup is here." The babies, Bortfeld explains, also listened to a different name paired with another word, such as "Autumn's bike is here." After the babies were exposed to the sentences, they were only allowed to hear the target word, "cup" or "bike." The babies, Bortfeld says, preferred listening to the word that had followed their own names as opposed to the ones that had not.
To ensure a baby recognized the target word that followed its name, Bortfeld had the babies listen to the two individual target words again, this time with two new random words. In this scenario, a baby, she says, listened longer to the target word that had followed its name in the previous experiment. The baby listened to the other target word that did not follow its own name for as long as it listened to the two new random words.
"Babies appear to use highly familiar words -- their names for example -- to anchor their early learning of other word forms, and if their name is the first word they recognize, then we're tapping into the process at the earliest stage possible," she explains.