“I don’t think it’s possible to overstate how important stereotypes are,” she said at a panel in Davos, Switzerland, where the annual World Economic Forum is being held this week. The problem is “at the root of the gender gap we face,” she said.

Sandberg, author of bestseller “Lean In: Women, Work, and the Will to Lead,” said the presence of stereotypes in advertising reinforces them in real life. And there was some new data on hand to help prove it.

Sandburg delivered her comments alongside Keith Weed, the chief marketing officer of conglomerate Unilever. The company, which owns brands like Dove and Ben & Jerry’s, committed last year to eliminating all sexist stereotypes from its advertising after finding that just 2% of ads show intelligent women. Weed said Wednesday that just 3% of ads show women in positions of power, and 1% present women as having a sense of humor.

A new study released Wednesday by food giant Unilever—based on 9,000 respondents—found that 77% of men believe that a man is best suited to lead a high stakes project. But men are not alone in their bias. The report shows 55% of women feel the same way.

“We’re as good as it gets and we have the same bias,” Sandberg said, referring to the Davos audience, whose members had trudged through snow and freezing temperatures to pack the early morning session.

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Sandberg and Weed also emphasized that Unilever’s stereotype-free ads have resonated with consumers.

Eliminating tired gender typecasts “is the right thing to do and it’ll make us more successful,” Sandberg says.

This story has been updated to clarify Sandberg’s remarks.