Young children have more sophisticated thought processes than you might imagine.
A review article in the journal Science by Alison Gopnik of the University of California, Berkeley, sums up a swath of research suggesting that preschoolers can make deductions about cause and effect, infer preferences and test hypotheses.
"New empirical work shows that young children learn from statistics, experiments (i.e., play) and from the actions of others in much the same way that scientists do," Gopnik writes.
Here's an experiment to demonstrate: Gopnik and colleagues showed children a device called a "blicket detector," which is a box that plays music in response to certain blocks being placed on it. Block A activated music by itself, block B did not, but both A and B together would activate music. The researchers found that the 2-, 3- and 4-year-old children were able to figure this out and make the music play.
A 2011 study in the journal Cognition showed a similar effect. That experiment involved plastic beads that can attach to each other to make a larger structure. Individual beads were placed on a machine and one group saw that only some beads made the machine work, whereas the second group saw that all beads did. Then, the kids got two new beads hooked together to play with. In the group where only some beads led to the machine going, kids pulled the beads apart and tested them separately. In the other group, they did not.
The beliefs of young children are also influenced by statistical evidence. A 2007 study in Developmental Psychology found that preschoolers could more easily point to something as a "cause" when it went along with their theories, than when it went against their theories.
Such studies drive home the point that children's play isn't frivolous; it's actually utilizing a degree of scientific thinking, she writes. It may even suggest that older students and adults could benefit from learning scientific concepts in a more observational "play"-oriented way, rather than just being talked at.
Gopnik argues that this research has profound implications for policy. She says that policy-makers "systematically underestimate the intellectual capabilities of preschoolers," and that the scientific work that children demonstrate in experiments like these is "more cognitively challenging, in fact, than most school work."