apologies if this has been posted before
Child's play is all a question of scale, say scientists
Tim Radford, science editor
Friday May 14, 2004
The Guardian
Researchers have unravelled one of the mysteries of the two-year-old mind: why toddlers try on dolls' shoes and try to drive tiny cars.
It's simple. They haven't mastered scale. A team from Northwestern University, the University of Virginia and the University of Illinois report in Science today that they videotaped children aged 18 to 30 months trying to slide down slides too small for them, trying to squeeze into miniature cars and trying to sit in dolls' chairs.
"Even infants can discriminate the size of objects, so the question is why children sometimes ignore the fact that the objects are so small," said David Uttall of Northwestern.
The study seems to confirm a theory of how the brain works: that two areas deal with visual information. One recognises and pigeon-holes objects ["That's a chair!"]. The other decides how to use the information ["I could sit down!"]. People recovering from severe stroke often have problems coordinating the information. Now it seems that very young children have to learn to do the same thing.
The children were left in a playroom with a pedal car big enough to sit in, a child-sized chair and an indoor slide. Then they were taken for a walk and when they got back they found only miniature replicas of the big objects. Yet 25 of the 54 children made 40 errors of scale, trying to slide down the tiny slide, or squeeze into the miniature car.
"In scale errors, the usual seamless integration between the two systems in the brain momentarily breaks down, and the size of an object is not incorporated into the child's decision to act on it," said Judy DeLoache, of the University of Virginia. "However, once the action begins, children do use size information to adjust the motor behaviour."