Here’s a riddle: Why would a Hurricane Alexandra be deadlier than an identical Hurricane Alexander?

Because females don’t get respect. Not even 100 mile-per-hour typhoons, if they’re dubbed with female names.

Researchers find that female-named hurricanes kill about twice as many people as similar male-named hurricanes because some people underestimate them. Americans expect male hurricanes to be violent and deadly, but they mistake female hurricanes as dainty or wimpish and don’t take adequate precautions.

The study, published in the Proceedings of the National Academy of Sciences, underscored how unconscious biases shape our behavior — even when we’re unaware of them.

Researchers examined the most damaging hurricanes between 1950 and 2012, excluding a couple of outliers like Katrina in 2005. They found that female-named storms killed an average of 45 people, while similar hurricanes with male names killed about half as many.

The authors of the study, Kiju Jung and others at the University of Illinois at Urbana-Champaign and Arizona State University, also conducted experiments asking people to predict the intensity and riskiness of a hurricane. When asked about a male hurricane, like Alexander, people predicted a more violent storm than when asked about a female hurricane, like Alexandra.

Likewise, research subjects were more willing to evacuate to avoid Hurricane Victor than when it was Hurricane Victoria. The more masculine the name, the more respect the hurricane drew. The researchers estimated that changing the name of a hurricane from Charley to Eloise could nearly triple the death toll.

Women were as likely as men to disrespect female hurricanes.

We often assume that racism or sexism is primarily about in-your-face bigots or misogynists, but research in the last couple of decades — capped by this hurricane study — shows that the larger problem is unconscious bias even among well-meaning, enlightened people who embrace principles of equality.

This affects the candidates we vote for, the employees we hire, the people we do business with. I suspect unconscious bias has been far more of a factor for President Obama than overt racism and will also be a challenge for Hillary Rodham Clinton if she runs for president again.

“It’s a mistake to assume that gender bias is only or mainly about misogynists,” said Susan Fiske, a psychology professor at Princeton University and the editor of the hurricane study. “Much gender bias is more automatic, ambiguous and ambivalent than people typically assume.

“Gender bias is not mostly about ‘I hate them, I hate them,’ ” she added. “A lot of it is about ‘I cherish them because they are nice, even if incompetent and needing protection.’ ”Yale researchers contacted science professors at major research universities and asked them to evaluate an application from a (mythical) recent graduate for a laboratory position. The professors received a one-page summary of the candidate, who in some versions was John and in others Jennifer.

On a scale of 1 to 7, with 7 the highest, the professors rated John an average of 4, and Jennifer a 3.3. On average, the professors suggested a salary for Jennifer of $26,508, and $30,328 for John. Professors were more willing to mentor John than Jennifer.

The professors’ assessments were unrelated to their own age or gender.

Other studies have reached similar conclusions, often by sending out identical résumés for job applicants — some with a female name and some with a male name. The male versions do better.

For example, evaluators assess the C.V. of “Brian Miller” as stronger than that of an identical “Karen Miller.” Stanford Business School students who read about “Heidi” rate her more power-hungry and self-promoting than those who read about an otherwise identical “Howard.”

While virtually all voters say today that they would vote for a qualified woman for president (only 30 percent said so in 1930), experiments by Cecilia Hyunjong Mo of Vanderbilt University suggest that in practice people favor male candidates because they associate men with leadership.

Professor Mo found that people, when asked to make pairs of images, have no trouble doing so with male names and words like “president” or “governor.” But some struggle to do so quickly with female names, and those people are more likely to vote for male candidates.

“There appears to be a gulf between our conscious ideals of equality and our unconscious tendency to discriminate at the ballot box,” Mo writes.

I suspect that unconscious biases shape everything from salary discrimination to the lackadaisical way many universities handle rape cases. They also help explain why only 4.8 percent of Fortune 500 C.E.O.’s and 18.5 percent of members of Congress are women.

This deep bias is as elusive as it is pernicious, but a start is to confront and discuss it. Perhaps hurricanes, by catching us out, can help us face our own chauvinism.