WASHINGTON, D.C. -- Something extraordinary happens between 18 and 24 months of age. In that brief span, toddlers take giant strides in their ability to visually inspect, recognize and manipulate various items. This achievement puts toddlers on par with adults given comparable tasks.
This developmental leap has been tracked for the first time by researchers at Indiana University in Bloomington who have created a special head-mounted camera that toddlers wear as they play with toys.
The device allowed the team to measure expansion of object recognition among toddlers. This development feeds into rapid advances made during the same time period in the ability to learn objects' names and to engage in pretend play, a basic form of symbolic thinking, psychologist Linda Smith said while describing the work July 24 in Washington, D.C., during the annual meeting of the Cognitive Science Society.
"Something very important happens in visual object recognition during this six-month period that then affects many other developing cognitive systems," Smith asserted.
These latest findings support the view that general mental capacities, such as perceiving and exploring objects, give rise to specific skills, such as recognizing objects' names, remarked psychologist Jeffrey Elman of the University of California, San Diego.
An influential opposing view holds that higher-order cognition, such as language and symbolic thought, stands apart from visual perception and other basic mental functions.
In order to track what children look at as they explore objects, Smith and her colleagues constructed a comfortable, head-mounted apparatus for toddlers. Each child wears a headband with a tiny, adjustable camera placed between and just above the eyes. A cord connected to the headband transmits video signals to a computer for a thorough visual analysis.
One head-cam study, led by Indiana's Alfredo Pereira, found that, from 15 to 30 months of age, children begin to prefer viewing objects from the same angles that adults do. This visual orientation, known as the planar view, focuses on an object's top, bottom or side.
Making natural head movements while looking at real-world objects, along with viewing objects from a planar perspective, yields copious information about those objects, Smith said.
Visual orientations that show more than one side of an object, such as a three-quarter view, prove especially useful in assessing static items, such as those in photographs, she noted.
The researchers gave eight objects, one at a time, to each of 30 toddlers to play with as they sat on a chair near a parent. Half of the objects were familiar, such as an airplane and a cup. The rest were items that preserved the basic structure of airplanes, cups and other familiar items but lacked identifying details.
Head-cam data indicated that, from 15 to 30 months of age, children increasingly favored planar views of both familiar and novel objects. This trend especially characterized toddlers who had vocabularies of at least 100 nouns.
Planar views may offer a prime look at buttons to be pushed, handles to be grabbed and other clues to objects' functions, Smith suggested. That knowledge then fuels learning of objects' names, in her view.
A second study, led by IU Bloomington's Sandra Street, examined the ability of 42 toddlers to insert three differently shaped objects into appropriately shaped openings. Participants were split between 18-month- and 24-month-olds. This ability has often been used to test for developmental delay in toddlers, but little is known about how the ability develops over time.
The younger kids "failed miserably," Smith said. Older children immediately succeeded on this task, performing at an adult level.
Only the 24-month-olds looked at objects with a consistently planar view.
Intriguingly, pretend play--say, using a laundry basket as if it's a car--also emerges between 18 and 24 months of age. Upon learning to recognize objects having abstract shapes, toddlers may be prepared for symbolic forms of play, Smith hypothesized.
By Bruce Bower August 16th, 2008; Vol. 174 #4