Learning curve not so smooth

Preschoolers often achieve mind reading milestone in fits and starts

WRONG AGAIN  Preschoolers take a variety of paths in the course of learning that others can have errant beliefs, such as assuming a toy is in a basket when it has been moved to a box, a new study finds. Kids often go back and forth in displaying this type of social knowledge rather than following a smooth learning curve.


Many preschoolers take a surprisingly long and bumpy mental path to the realization that people can have mistaken beliefs — say, thinking that a ball is in a basket when it has secretly been moved to a toy box. Traditional learning curves, in which kids gradually move from knowing nothing to complete understanding, don’t apply to this landmark social achievement and probably to many other types of learning, a new study concludes.

Kids ranging in age from 3 to 5 often go back and forth between passing and failing false-belief tests for several months to more than one year, say psychologist Sara Baker of the University of Cambridge and her colleagues. A small minority of youngsters jump quickly from always failing to always passing these tests, the scientists report October 20 in Cognitive Psychology.

“If these results are replicated, it will surprise a lot of researchers that there is such a low level of sudden insight into false beliefs,” says psychologist Malinda Carpenter, currently at the Max Planck Institute for Evolutionary Anthropology in Leipzig. Early childhood researchers generally assume that preschoolers either pass or fail false-belief tests, with a brief transition between the two, explains Carpenter, who did not participate in the new study. Grasping that others sometimes have mistaken beliefs is a key step in social thinking.

False-belief understanding may start out as something that can be indicated nonverbally but not described. Human 2-year-olds and even chimpanzees tend to look toward spots where a person would expect to find a hidden item that only the children or apes have seen moved elsewhere (SN Online: 10/6/16).

Numerous investigations suggest that neurologically healthy kids between ages 3 and 5 consciously appreciate when others have formed mistaken beliefs. But those studies report average scores on false-belief tests for groups of preschoolers. That leaves unexamined how individual kids progress — or not — as mind readers.

Baker’s team generated individual scoring profiles for 52 children repeatedly assessed for false-belief understanding between ages 3 and 5. Trials occurred over roughly one to two years. Two types of false-belief tasks were alternately presented about every two to six weeks, either at a preschool, in a lab or at a child’s home.

In one task, an experimenter used pictures to help describe a situation in which someone moves an object from one location to another once a friend leaves — say, taking a ball from a basket and putting it in a toy box. Children were asked where the friend would later look for the object.

In a second task, children observed a container’s unexpected contents, such as a sock in a crayon box or a toy cow in an egg carton. Kids reported what they originally thought was inside the container and what another person would think is inside it.

Nine children, including some of the youngest ones, passed their first three trials. All except one of the nine continued to pass trials at a high rate. The remaining 43 children failed at least one of the first three trials. A statistical analysis calculated the likelihood that a series of scores for a particular child reflected gains, losses or no change in false-belief understanding.

Five of the 43 children achieved rapid insights into false beliefs, consistently passing trials immediately after a string of failed trials. Another 22 youngsters showed different patterns of improvement, such as going from a 12 percent likelihood of passing trials to a 50 percent chance by the study’s end. None of them moved gradually and steadily from failing to passing false belief tests. Smooth learning curves are statistical illusions created by averaging group scores, the researchers suspect.

Four kids started out failing false-belief tests and showed no signs of improvement over time. Another 10 children sometimes passed and sometimes failed throughout the study. Statistical profiles were inconclusive for two children.

Related findings, although based on group statistics, nonetheless suggest that grade-schoolers shift among various problem-solving strategies when learning mathematical concepts (SN: 3/17/01, p. 172). Baker’s statistical method could enhance the study of how individual children develop math skills and other forms of reasoning, says psychologist Rose Scott of the University of California, Merced.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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