The ability of infants to recognize speech is more complicated
than was previously thought, says a new study.
Researchers at the Department of Psychology, New York University
(NYU), have shown that babies, even nine months old infants, are capable of
distinguishing between speech and non-speech sounds in humans and animals.
Athena Vouloumanos, an assistant professor at NYU and the study's
lead author says that their research has proved that infants' speech perception
is resilient and flexible and that the recognition of speech is much more
refined than what was earlier thought.
Adults' speech perception is fine-tuned to detect speech among a range
of various different sounds but not much is known about babies' capabilities to
assess sounds. Knowing this will help us understand how early our speech
In order to evaluate the earliest time at which speech is
perceived, the researchers studied infants' responses to recorded versions of
human and parrot speech and non-speech sounds.
Human speech (an adult female voice) and parrot speech sounds
included the words "truck," "treat," "dinner,"
and "two."The recorded parrot speech came from Alex an African Gray
parrot, that had the ability to talk and reason and whose behaviors were
studied by Irene Pepperberg, psychology researcher. The adult human non-speech
sounds included whistles and a clearing of a throat while the parrot non-speech
sounds consisted of squawks and chirps.
Infants, cannot verbally communicate, however, they tend to look
longer at what they think is interesting or unusual. This was the tool to
identify their speech recognition too.
Besides, the sounds were paired with a series of visuals such as a
checkerboard-like image, faces of adult females and a cup.
The results of the study showed that infants listened longer to
human speech in comparison to human non-speech sounds, regardless of the
visuals. This clearly demonstrated the ability to recognize human speech
without considering the context.
When clubbed with human-face visuals or artifacts like cups the
infants listened to non-human speech, such as parrot speech, longer than they
listened to non-speech. It appeared as though the infants' preferred parrot
speech in the same manner they did human speech sounds. However the infants
were able to distinguish animal speech from non-speech, but only in some
The study helped to confirm that infants have the ability to
detect various types of speeches, even if they required visual cues to assist
them in understanding the process.
The results of the study have appeared in the
journal Developmental Psychology