More Than Child's Play; October 2011; Scientific American Magazine; by Sharon Begley; 1 Page(s)

If your brownies came out too crispy on top but undercooked in the center, it would make sense to bake the next batch at a lower temperature, for more time or in a different pan—but not to make all three changes at once. Realizing that you can best tell which variable matters by altering only one at a time is a cardinal principle of scientific inquiry.

Since the 1990s studies have shown that children think scientifically—making predictions, carrying out mini experiments, reaching conclusions and revising their initial hypotheses in light of new evidence. But while children can play in a way that lets them ascertain cause and effect, and even though they have a rudimentary sense of probability (eight-month-olds are surprised if you reach into a bowl containing four times as many blue marbles as white ones and randomly scoop out a fistful of white ones), it was not clear whether they have an implicit grasp of a key strategy of experimental science: that by isolating variables and testing each independently, you can gain information.