At a recent Authors@Wharton event, Wharton’s Adam Grant spoke with Malcolm Gladwell about his latest bestseller, ‘Revenge of the Tipping Point.’

Grant put the question in a business context, saying that studies on startups show that when founders emphasize a culture fit when hiring new employees, the business is less likely to fail at first. But as the company grows, that monoculture no longer works. “Once you become a bigger organization, you end up too homogenous, and you have a lot of groupthink, and it becomes harder to change and innovate,” Grant said.

Gladwell said he’s come to believe in quotas because diversity’s strength is in numbers.

“It’s not just about having people who are different,” he said. “It’s about having people who are different in sufficient numbers so that they can be themselves, and they can change the culture of the group that they belong to.”