There is a growing body of evidence that very young children — too young even to talk — still know plenty of words. When our kids were very young, it was quite clear that they knew the meanings of many more words than they could actually produce. When they couldn’t speak at all, they understood words like “Mommy,” “bottle,” and “diaper.” When they were older and could say those words but not complete sentences, they understood more complicated phrases like “go into the kitchen and bring me your sister’s sippy cup.”
But is there something special about words? Or could babies learn to associate any sound with a meaning? So far the evidence suggests that words are special. Twelve-month-olds, for example, can be trained to recognize words much more quickly than other sounds. But still, this might be due to the fact that these babies have themselves already learned a considerable amount of language. Do younger babies show the same preference for words over other sounds?
Anne Fulkerson and Sandra Waxman enlisted 128 infants — half of them six months old, and half twelve months old — and showed them each eight slide-show pictures of either dinosaurs or fish. With each picture, half the babies heard a recording of a woman’s voice identifying the picture with a nonsense word, like this: “Look at the toma! Do you see the toma!” The other babies heard a series of tones at a constant pitch for the same duration as the woman’s voice. After viewing the series of pictures — either eight different dinosaurs or eight different fish, they saw one final slide with both a picture of a dinosaur and a fish (neither of which they had seen before).
If a child has been trained to recognize the category “dinosaur” and has seen many dinosaurs in a row, then dinosaurs shouldn’t be as interesting as fishes. We would expect the babies to look at the fish for a longer period than the dinosaur. Here are the results:
Both younger and older infants spent significantly more time looking at the category they hadn’t seen before when they had been trained using words. But neither group spent significantly more time looking at the new categories when they had been trained with tones. In both cases the babies saw the same animals and heard consistent audio along with each animal, but when that audio wasn’t language, the children didn’t appear to learn that all the animals belonged to the same category.
Fulkerson and Waxman argue that this shows that early language learning isn’t simply a process of associating particular sounds with categories. Instead, even very young infants only appear to learn categories when those categories are associated with words. Note that this doesn’t mean that tones themselves couldn’t be seen as words. A baby could be taught that an electronic “beep” means dinosaur by showing her pictures of dinosaurs and saying “do you see the (BEEP)?” This study simply shows that tones in the absence of a language framework aren’t treated as language. Even babies as young as six months can tell the difference between sounds that are intended to communicate and non-language sounds.
Fulkerson, A., Waxman, S. (2007). Words (but not Tones) facilitate object categorization: Evidence from 6- and 12-month-olds. Cognition, 105(1), 218-228. DOI: 10.1016/j.cognition.2006.09.005