Exposure to wider array of objects speeds word learning

Perry LK. Psychol Sci. 2010;doi:10.1177/0956797610389189.

Eighteen-month-olds who played with a broader array of objects named by shape — for example, groups of bowls or buckets that were less similar in material, size or features — learned new words twice as fast as those who played with more similar objects, according to a recently published study.

One month after the training, toddlers who had been exposed to the diverse objects were learning an average of nearly 10 new words per week. Children in the other group were picking up four new words a week — typical for children that age without any training.

Researchers from University of Iowa enrolled 16 children who knew about 17 object names when the study began. Half of the children were taught names of objects by playing with groups of toys that were nearly identical; the other half used toys that differed significantly — for example, a small, cloth, jack-o-lantern bucket; a trash bucket with no handle; and a traditional plastic bucket.

When tested on unfamiliar objects that fit into the categories they had been taught, children in the variable group performed better. This showed an ability to generalize the knowledge, the researchers wrote in the journal Psychological Science. They added that all of the children given extra training with words figured out that shape was the most important distinguishing feature when learning to name solid objects. This attention to shape, called a “shape bias,” is not typically seen until later in development. The researchers wrote that boys and girls who were exposed to a wider array of objects took the knowledge a step further, also learning when not to attend to shape. Tots in the variable group learned, for example, to focus on material rather than shape when hearing names for non-solid substances.

“Knowing where to direct their attention helps them learn words more quickly overall,” Lynn Perry, a University of Iowa doctoral student in psychology, said in a press release. “The shape bias enhances vocabulary development because most of the words young children learn early on are names of categories organized by similarity in shape. And, developing the ability to disregard shape for non-solids helps them learn words like pudding or milk.”

In additional tests, researchers looked at whether the tots learned names of new objects by focusing on substance or shape. The variable group tuned into shape for solids but material for non-solids, distinction children are not typically capable of making until the age of 3, when their vocabulary reaches 150 nouns.

Further investigation is necessary to pinpoint exactly why the variable group had more success, but the researchers said their study is the first to show that variability at the local level can help children learn something more global about the importance of particular object features for different categories of things.

Children in the toddler years are in a rapid period of growth, with an associated explosion of learning. This study highlights the benefit of a parent providing the infant and toddler with a wide variety of stimulation and experiences, as he or she learns from seeing, hearing, and doing. The growing brain is a network of interconnected circuits, with the child’s language development benefitting not only from what is heard but what is seen and touched as well.

—Paul H. Lipkin, MD,

Infectious Diseases in Children Editorial Board member

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