SelfhelpMagazine

by Sven Mattys, Ph.D. & Peter Jusczyk, Ph.D.

When do babies start to understand words as words? A series of eight experiments with infants has provided evidence that even at eight-and-a-half months, they seem sensitive to word boundaries.

Psychologists Sven Mattys, Ph.D. & Peter Jusczyk, Ph.D., of the Departments of Psychology and Cognitive Science at Johns Hopkins University investigated how babies find the beginnings and ends of words in utterances.

Specifically, would infants sometimes incorrectly group the end of one word with the beginning of another word? For example, would babies respond to the sound of "dice" within "cold ice" or "red ice" in the same way they would respond to "dice" in "two dice"?

Mattys and Jusczyk used the widely validated "head turn preference procedure," in which infants sit in a three-sided booth on their caretaker's lap. A green light flashes in front when they look ahead in "rest" position.

To start the experiment, a computer-controlled red light flashes on either the left or right side of the booth, drawing the infant's attention. A concealed loudspeaker behind that light plays the experimental word or passage.

A hidden observer watches the infant through a peephole, recording for how long the infant listens to the sample (in other words, looks at the red light associated with the loudspeaker). The researchers compared how long the infants paid attention to the different types of samples. "Infants seem to be more interested when they can pick up something they recognize as familiar amidst the new words of the passages," says Mattys. "It's as if you heard your name in a conversation at a table next to yours." They found that English-learning infants were considerably delayed in their ability to segment words that start with vowels instead of consonants, indicating that although word-segmentation capacities start relatively early, the full development of these capacities is a gradual process extending well into the second year. The infants studied failed to segment words starting with vowels until 16 months of age. Fewer spoken words start with vowels, which provide more subtle acoustic cues than the more explosive consonant sounds. The study authors state that the full development of word-segmentation capacities may start relatively young but they require well into the second year to develop.

Reference:

"Do Infants Segment Words or Recurring Contiguous Patterns?," Sven L. Mattys & Peter W. Jusczyk; Journal of Experimental Psychology: Human Perception and Performance, 2001, Vol. 27, No. 3. This information received from the American Psychological Association (APA), in Washington, DC.