Investors tend to get overconfident about the market, but no one is really good at predicting the future—including the experts, "Freakonomics" co-author Stephen Dubner told CNBC's "Closing Bell" Tuesday.
"We tend to believe more in ourselves than we should," he said. "We all think that we can do better than average and that can be a trap. You gotta play it smart, you gotta lean to the index when you feel you need to and then depend on really smart guys … if they are indeed much smarter."
It's not the first time Dubner has warned about stock-picking advice. Last month on CNBC Europe, he said, "If you look at stock-picking advice, you find that the experts … are generally about as good as monkey with a dartboard."