Although women make up 40% of the global workforce, they hold only 24% of senior management roles around the world — a figure that has not changed significantly over the past decade. Of chief executive officers of S&P 500 firms, only about 5% are women. Why aren’t more talented women moving up? Researchers have pointed to an array of reasons, from explicit discrimination to promotion processes that quietly favor men, but one of the most perplexing is that women themselves aren’t as likely as men to put themselves forward for leadership roles through promotions, job transfers, and high-profile assignments.