July 18, 2012
Infant Speech Recognition More Advanced
Connie K. Ho for redOrbit.com — Your Universe Online
Sights and sounds are sensory details that are absorbed by a child early on. How much of that becomes recognizable to the infant is still being debated. According to researchers from New York University (NYU), an infant´s ability to recognize speech is more advanced that previously understood.
While it´s known that adults have a fine-tuned perception of speech and an understanding of ambiguous sounds, less is known about the ability of infants to make these kinds of language assessments. As such, a team of investigators from the Department of Psychology conducted a project on speech recognition and the findings are published in a recent edition of the journal Developmental Psychology. In particular, they found that infants as young as nine months can distinguish between speech and non-speech sounds in animals and humans. Researchers believe that these new findings help them better understand how early language recognition develops in children.
"Our results show that infant speech perception is resilient and flexible," remarked lead author Athena Vouloumanos, an assistant professor at NYU, in a prepared statement. "This means that our recognition of speech is more refined at an earlier age than we'd thought."
In the project, the researchers looked at the responses of infants from about nine months in age in relation to human, parrot, and non-speech sounds. The human, an adult female voice, and the parrot voice said words like “dinner,” “treat,” “truck,” and “two.” The adult non-speech sounds included things such as whistles and clearing voice, while the parrot non-speech sounds were chirps and squawks.
While infants cannot use verbal communication to show that they recognize the speech, the researchers measured the infants´ recognition by seeing how long the child looked at something that was interesting or unusual. As such, if the child looked at something for a longer time, then it was interpreted that child had some kind of recognition. In the study, the researchers paired the sounds with visuals such as a checkerboard-like image, a cup, and adult female faces.
Based on the results, the scientists believe that the non-human speech was more nuanced. The infants tended to listen to parrot speech longer and stare at the human-face visuals or human artifacts longer than they listened to the non-speech sounds. However, they found that this didn´t occur with other stimuli and that infants were only able to recognize animal speech from non-speech in certain situations.
"Parrot speech is unlike human speech, so the results show infants have the ability to detect different types of speech, even if they need visual cues to assist in this process," explained Vouloumanos in the statement.
The researchers concluded that there are parallels between child development of speech recognition and adult recognition of speech.
“The ability to decode atypical and degraded speech signals as intelligible is a hallmark of speech perception. Human adults can perceive sounds as speech even when they are generated by a variety of nonhuman sources including computers and parrots,” wrote the researchers in the article. “Like adults, infants may perceive a range of signals as speech.”