Huh, it might be that WOMEN KNOW BEST about their own lives. Who knew?!?!

Who knew? Women knew! Of course.

I am not sure I understand their point, did negotiation resulted in decreasing the salary against the offer? Or it had not increased enough to compensate for the originally low offer?  And what about men, had they participated as well?  The study was "gender-blind", so it would be interesting to see comparisons: "To determine if avoiding negotiations 34% of the time was financially wise, we examined how the distribution of wages changed when women were instead forced to negotiate every time. When women were forced to negotiate every time, women’s overall wages actually decreased. To put a finer point on it: final wages exceeded the initial wage offer at exactly the same rate as when they had a choice to avoid negotiations – 49% of the time — but the rate by which final wages fell short of the initial wage offer increased from 9 to 33%." 

51% of the time final wages did not exceed the initial wage offer.

I'd imagine in many of those cases the final wages just stayed the same.