Drs. Alissa L. Ferry, Susan Hespos, and Sandra Waxman, the authors of the study, are professors at the Department of Psychology at Northwestern University, in Evanston, Illinois, U.S.A.
The conclusion of their study will appear as an article entitled 'Categorization in 3- and 4-Month-Old Infants: An Advantage of Words Over Tones' (Volume 81 Issue 2, Pages 472 - 479; published online: March 24, 2010) in the March/April 2010 edition of the journal Child Development.
The three psychologists showed 46 infants'”who were healthy, delivered full-term, and heard primarily English in the home; and who ranged from three to four months of age'”a series of pictures of fish that were associated with either (1) words or (2) tones (beeps).
Half of them in each age bracket were randomly shown a picture and provided with a verbal word. (They were in the 'word' group.) The other half were shown a picture and provided a verbal beep. (They were in the 'tone' group.)
The cognition test was used to see if words play a role in cognition (acquisition of knowledge; learning) even at the early age of three months.
According to the Northwestern University News Center press release Talk to Your Babies' states that 'words influence infants' cognition from first months of life, 'Infants in the word group were told, for example, "Look at the toma!" --- a made-up word for fish, as they viewed each picture. Other infants heard a series of beeps carefully matched to the labeling phrases for tone and duration.'
Page two provides more details of the study.
The U.S. psychologists measured the amount of time it took each baby to look at each picture. A 'category' was formed when they looked at one picture longer than the other. Thus, the association was a categorization, per the researchers' results.
They concluded that even before babies learn to speak, words that they hear play an important part of their learning.
In fact, 'In the study, infants who heard words provided evidence of categorization, while infants who heard tone sequences did not.' [Northwestern University]
Further, 'For 3-month-old infants, words influence performance in a cognitive task in a way that goes beyond the influence of other kinds of sounds, including musical tones.'
And, 'The results, say the authors, were striking. The researchers found that although infants who heard in the word and tone groups saw exactly the same pictures for exactly the same amount of time, those who heard words formed the category fish; those who heard tones did not.' [Northwestern University]
Page three provides comments from two of the researchers.
Dr. Sandra R. Waxman, another author of the study, stated, "We suspect that human speech, and perhaps especially infant-directed speech, engenders in young infants a kind of attention to the surrounding objects that promotes categorization.'
'We proposed that over time, this general attentional effect would become more refined, as infants begin to cull individual words from fluent speech, to distinguish among individual words and kinds of words, and to map those words to meaning." [Northwestern University]