Adults focus on objects that will be most useful to them. But . . . children play with the objects that will teach them the most. In our study, 4-year-olds imagined new possibilities based on just a little data. Adults rely more on what they already know. Babies aren’t trying to learn one particular skill or set of facts; instead, they are drawn to anything new, unexpected or informative.

Part of the explanation for these differing approaches can be found in the brain. The young brain is remarkably plastic and flexible. Brains work because neurons are connected to one another, allowing them to communicate. Baby brains have many more neural connections than adult brains. But they are much less efficient. Over time, we prune away the connections we don’t use, and the remaining ones become faster and more automatic. Moreover, the prefrontal cortex, the part of the brain that controls the directed, planned, focused kind of intelligence, is exceptionally late to mature, and may not take its final shape until our early 20s.

In fact, our mature brain seems to be programmed by our childhood experiences — we plan based on what we’ve learned as children. Very young children imagine and explore a vast array of possibilities. As they grow older and absorb more evidence, certain possibilities become much more likely and more useful. They then make decisions based on this selective information and become increasingly reluctant to give those ideas up and try something new. Computer scientists talk about the difference between exploring and exploiting — a system will learn more if it explores many possibilities, but it will be more effective if it simply acts on the most likely one.

Babies explore; adults exploit.