In 7 different studies, the authors observed that a large number of thinking biases are uncorrelated with cognitive ability. These thinking biases include some of the most classic and well-studied biases in the heuristics and biases literature, including the conjunction effect, framing effects, anchoring effects, outcome bias, base-rate neglect, “less is more” effects, affect biases, omission bias, myside bias, sunk-cost effect, and certainty effects that violate the axioms of expected utility theory. In a further experiment, the authors nonetheless showed that cognitive ability does correlate with the tendency to avoid some rational thinking biases, specifically the tendency to display denominator neglect, probability matching rather than maximizing, belief bias, and matching bias on the 4-card selection task. The authors present a framework for predicting when cognitive ability will and will not correlate with a rational thinking tendency.
Even more interesting, in my view, is that higher-IQ people are more likely to behave rationally when they are told that a rationality issue is on the table, but less so otherwise.
If you are interested in issues of IQ, or for that matter overcoming bias, you should read Stanovich's work. As noted above, higher-IQ people seem to be just as guilty of "myside bias."
Stanovich has a new book summarizing some of the results, namely What Intelligence Tests Miss: The Psychology of Rational Thought. It is more idiosyncratic than the articles (he overcommits to one very particular model of the mind; cognitive laziness, without regard for margin) but recommended nonetheless. For those who care about these issues, a must.