Measures of general intelligence (IQ) have a long and controversial history. Most experts today agree on a few things: IQ is measurable; it stabilizes as early as age 5; and it is predictive of many positive outcomes, including educational and financial attainment. In popular culture, though, hyper intelligence is frequently linked to social awkwardness. The image of the exceptionally smart person who lacks common sense and can’t relate to people is a staple of TV and movies.

For better or worse, this stereotype has some basis in reality: scientific findings repeatedly have noted that at very high ranges, IQ tends to be inversely related to strong social and interpersonal skills (Gross 2002).

Given that interpersonal skills are crucial in the workplace, might markedly high IQ be a problem—particularly in high-level management? A number of articles, research findings, and blogs would have us believe so. Fast Company magazine (Azzarello 2012), for example, suggested that the high-IQ executive doesn’t listen well and can frustrate his or her team. Direct reports grow weary of asking for additional explanation; the “smart executive” grows resentful of needing to hold the hands of employees. Mael (2005) also suggests that often the very intelligent executive is markedly ineffective, in part because of tendencies to grow impatient, to “always be right,” and to refuse to “leave room for others to be smart as well.”

Despite such assertions, analysis of data from Korn Ferry’s assessments of upper level executives reveals no evidence of leaders being “too smart.” High IQ executives tend to be high performers, and the positive effect associated with IQ does not plateau. Some researchers agree with our verdict, finding a positive and even substantial effect on performance (Hunter and Hunter 1984), though others suggest that (within normal IQ ranges), IQ has little effect on executive performance (Sternberg 1997; Fernandez-Araoz 2001; Emmerling and Goleman 2003).

So to some extent the jury remains out on IQ. Does it have a positive effect? Negative? Is the effect only trivial? Why the inconsistent findings?

We at the Korn Ferry Institute hypothesized that whether a high IQ is an asset or a liability depends on the individual’s social-emotional makeup. We secured data on 209 upper level managers and executives to test our hypothesis. Each person had completed a comprehensive executive assessment that included a leadership performance simulation, and measures of IQ and self-awareness.

Self-awareness—which involves insight into one’s own behavior, strengths, motives, and weaknesses—is a primary component of emotional intelligence and is highly correlated with interpersonal skills. Self-aware executives understand the effect they have on other people and regulate their emotions and social behavior accordingly (Herwig, Kaffenberger, Jäncke, and Brühl 2010). They are more likely to be socially skilled and appropriately empathetic, and thus unlikely to display the impatience, poor listening, and related resentment noted in the blogs and articles about high IQ executives.

Statistical analyses confirmed our hypothesis. High IQ improves executive performance for those with elevated levels of self-awareness. For those whose self-awareness is low, increased IQ becomes a liability and detriment to managerial performance.

Stated differently, an organization can expect better leadership performance from an executive with low self-awareness and an average IQ than from one with low self-awareness and a high IQ.

Our results fall in line with well-established research tying strong socialemotional abilities (within average to high IQ level populations) with positive managerial performance. What is novel about our finding is that self-awareness actually appears to moderate whether high IQ is a positive or negative for business leaders.

In fact, self-awareness seems to matter more than intelligence. Unlike IQ, it shows an unqualified positive relationship with performance. This isn’t surprising: other studies of leadership performance have found that social-emotional factors have up to twice the impact of IQ (Goleman 1998; Womenetics 2014). Moreover, self-awareness—unlike IQ—seems to be malleable even well into adulthood (Davidson, Jackson, and Kalin 2000). Growth in self-awareness, then, is a potent development opportunity for those aspiring to the C-suite. It not only leads to more effective management generally, but also brings out the positive aspects of other characteristics in executives—including high IQ.