Through most of human history, our ancestors had children shortly after puberty, just as the members of all nonhuman species do to this day. Whether we like the idea or not, our young ancestors must have been capable of providing for their offspring, defending their families from predators, cooperating with others, and in most other respects functioning fully as adults. If they couldn't function as adults, their young could not have survived, which would have meant the swift demise of the human race. The fact that we're still here suggests that most young people are probably far more capable than we think they are. Somewhere along the line, we lost sight of – and buried – the potential of our teens.

[One way] researchers sometimes evaluate people's judgments is to compare those judgments with those of more mature or experienced individuals. This method has its limitations too, because mature or experienced individuals are sometimes so set in their ways that they can't properly evaluate new or unique conditions or adopt new approaches to solving problems.