The next time your children get filthy playing in the riverbed or taking apart the remote control, stop before you scold. Scientists say that this kind of play is actually like hands-on science experimentation for your kids; they're learning to decipher the world around them through exploration. Alison Gopnik, professor of psychology at the University of California at Berkeley, explains how these findings should change how we educate our children.

Play is something we all do--it seems so natural, it feels a little bit ridiculous to ask why we need it. But psychology professor Alison Gopnik explains some profound benefits, and tells us about a noticeable shift that happens somewhere between age 3 and 6--a shift that causes ...