If you go to a language clinic with a 2-year-old who isn't talking yet and she picks up a block and moves it around like a car, the language therapist will probably reassure you that your child will talk soon, said Indiana University psychology professor Linda Smith, PhD, at APA's Annual Convention.
"But if that child doesn't engage in symbolic play, the language therapist is worried," she noted.
Psychologists have long known that symbolic play, substituting one object for another, is a strong predictor for language development, noted Smith, but why that is has long been a mystery.
New research by Smith and her colleagues is shedding light on the area and, more generally, on how playing with objects can promote language development and vice versa. Researchers are finding that the ability to see the abstract shapes in everyday objects may underpin both abilities.
"Development is a series of weird loops," said Smith. "It's a cascade of mutually interacting causes and consequences."
Tube to telescope
Give children toys and wait for them to engage in imaginative play and "you can be waiting around all day," said Smith. But in an as-yet-unpublished study, Smith and her colleagues devised a way to help children along.
The researchers separated 36 children into two groups: those with more than 100 nouns in their vocabularies and those with fewer. They then gave the children sets of toys with one item missing. One set, for example, included a doll, a pillow and a sheet, but no bed, just a block. Another included a road and a chair, table and house, but no person, just a wooden peg. The researchers found that the children with the larger vocabularies tended to use the block as a bed and the peg as a person more than the other children.
That may be because the children with fewer words simply hadn't yet developed an abstract mental representation for "bed" that allowed them to see the analogy to a rectangular block, said Smith.
While language affects play, play can also affect language, said Smith. In a 2005 study, published in Cognitive Science (Vol. 29, No. 4), Smith and her colleagues gave 2-year-olds an object they called a "wup" - a fuzzy dome with two wing-like protrusions. They asked the children to move the wups either up and down or side to side, thus emphasizing the vertical or horizontal axis of the object. The researchers then asked which of two objects - a tall, thin one or a wide, short one - was the wup. The children who had moved the object up and down overwhelming chose the tall wup, while the others chose the wide one.
Deciding what objects belong to which categories is not just a lab exercise, it's the basis for language, said Smith. Knowing that an object is a "chair" for instance may seem effortless, but individual chairs can all differ vastly in size, shape and color. Children manage to construct a general definition of "chair," though no one knows exactly how they do it.
"There are a lot of theoretical proposals about how people recognize shape at this level ... but there's no consensus in the literature," said Smith.
What Smith and others have demonstrated, however, is that a foundation for this ability -- and the aptitude to learn new nouns -- may rely on a capacity to pull out the abstract shapes in everyday objects.
In a 2002 study published in Psychological Science (Vol. 13, No. 1), Smith and her colleagues brought in 1-year-olds for weekly play sessions. During the hourlong sessions, an experimenter and child played with objects with made-up names, such as "wif" and "dax." Two wifs might differ in texture, color and size, but they always had the same shape.
The adults told the children in the experimental group the object's name, and then played with it, saying things like "Let's put the wif in the bucket" and, "That's not a wif. Let's put that away." The control group, in contrast, didn't get such instruction.
Before and after the training, the researchers assessed the children's vocabulary, and found that the control group's real-world noun vocabulary had doubled in the eight weeks - an impressive feat. But the shape-trained children did even better, with their noun vocabulary more than tripling.
"Training kids to attend to object shape in the lab increased their object naming in the real world," said Smith.
The converse is also true, found Smith, citing results from a 2003 study in Psychological Science (Vol. 14, No. 3). In it, she found that 18- to 24-month-old children with large vocabularies tend to more readily recognize three-dimensional caricatures of everyday objects. When given a gray Styrofoam toy with the characteristic sphere-on-cone shape of an ice cream cone, children who knew more than 100 nouns were more likely to recognize it as ice cream than children who knew fewer than 100 nouns.
In fact, parents who want to teach their children to pay attention to objects' shapes - and increase their noun learning - need not do much more than go shopping for age-appropriate toys. Toys for infants and toddlers often look like caricatures from Smith's study - a fire truck for a 1-year-old is little more than a red, rectangular box with wheels - while one for a 5-year-old has grommets, ladders and a hose. Playing with the abstract toys may give young children a leg up on noun learning, said Smith.
Taken together, Smith's research suggests that learning object names is affected by a variety of developmental processes, and constructing that vocabulary, in turn, attunes children to abstract shapes and primes them to learn even more nouns.
"We know that something important in visual object recognition is happening between 18 and 24 months, and it involves and impacts many developing systems," Smith said.
This session was sponsored by APA's Board of Scientific Affairs.