There are a ton of different explanation for the persistent pay gap between men and women out there, but one that comes up repeatedly is that women, constrained by social expectations to be "nice," simply don't ask for raises as often as men.

It sounds plausible, but according to a shocking new study there's one little problem with this hypothesis: It doesn't appear to be true.

Actually, women do ask.

To test the idea that women are simply shyer about asking for a pay bump, a team of business school professors mined a unique data set from a survey of 4,600 randomly sampled Australian workers employed at 840 different workplaces that specifically asked about how people's compensation was determined, including whether they asked for a raise and what the result of that request was.

The first surprise for the researchers came when they compared the rate at which men and women ask for raises -- it was the same. About 70 percent of employees of both genders in the sample had said they had requested a pay increase.

But the real shock came when the team analyzed the outcome of those requests. While men were successful in getting a raise 20 percent of the time, women only got a pay bump 16 percent of the time. That means men are 25 percent more likely to get the raise they asked for, though things improved among younger workers. Female employees under 40 got raises at the same rate as their male colleagues.

The data also debunk the idea that women don't ask because they fear rocking the boat or being labeled as aggressive: 14.6 percent of men said they feared the impact of such a request on workplace relationships, while only 12.9 percent of women had that particular worry.

"We were shocked," Amanda Goodall of Cass Business School, who participated in the study, commented. "We thought that we would find women were genuinely more reticent, and less likely to ask for a pay rise. And that is not what we found."

What's to be done?

Unfortunately, the research doesn't uncover just why this difference exists, nor does it offer solutions. But it's good to know that one theory as to why women earn less than men is quite probably wrong. Now all researchers have to figure out is why women are denied raises disproportionately and what companies need to do to change that.

Do these findings line up with your personal experience?