Anyone who thinks female leaders are the only ones judged by their appearance hasn’t been listening to many business school professors.

In recent years, economists have examined the link between men’s height and their job status (being taller increases the likelihood of attaining a management job). Finance professors have studied the link between male CEOs’ looks and how much they’re paid (those whose appearances were rated as “competent” earned more). Others have even looked at the face shape of male CEOs and the amount of hair on men’s heads (wider faces were tied to better performance, while bald men were thought to be more dominant leaders).

And now, researchers have examined yet another tie between physical traits of male leaders and their success. Professors from Duke University’s Fuqua School of Business and the University of California at San Diego examined how the depth of a male CEO’s voice affects his career.

In a study of nearly 800 CEOs, they found that a 1-percent decrease in voice pitch is associated with a $30 million increase in the size of the firm managed — and therefore, $19,000 more in annual pay. (One can almost hear the Barry White impressions starting in the next cubicle.)

The researchers aren’t clear about why bass-voiced CEOs appear to be correlated with running bigger companies. One proposal they make is that in larger firms, which have more employees involved in decision-making, “subordinates might acquiesce to a deep-voiced CEO because of the leadership capacity his vocal pitch connotes.”

Basic evolution may also play a role. Studies have shown that deep-voiced men father more children, the researchers note. So while it may be a little uncomfortable to think of your baritone boss as an evolutionary alpha male, it’s possible that such “a trait known to indicate success in biological competition” might lead to success in career contests, too.

Linking physical characteristics like the pitch of a man’s voice to his leadership potential might seem a little trivial. And of course, to some extent it is: Boards of directors and executive search firms are hardly going to start putting the width of a candidate’s face or his degree of baldness on the resumes of their CEO candidates. (The authors of the voice paper seem to get this: “Leaders are exceedingly complex and not easily summarized,” they write, “be it by scale, tape measure, or microphone.”)

But studies showing linkages between superficial characteristics and career success are nevertheless a reminder that when it comes to choosing leaders — male or female — our subconscious viewpoints about physical traits still have a way of coming out. Directors might put experience, industry networks and leadership ability on the list of credentials they’re seeking in a future manager. They may go out of their way to find a diverse set of candidates and think they’re leaving their biases at the door. But whether it’s the size of an executive’s waistline or the scale of his height, it’s good to remember there are many factors that influence our ideas about who looks the part. Or at least, who sounds like it.

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