Are women rated lower because they are less agressive?

The headline, Testosterone and the Trading Floor, caught my eye, but what came next, "Chess has become something of a hot new way to study behavioral economics...", grabbed my attention. A fellow named Ryan Sager has written an article on Money & Your Mind over at SmartMoney.com. He writes, "The most recent data point on why men and women invest differently comes from a new paper by Christer Gerdes and Patrik Gränsmark of Stockholm University, looking at differences in play between male and female expert chess players. Chess has become something of a hot new way to study behavioral economics, in that there are vast amounts of data available and because each move in chess represents, in the words of one study, “a well-defined problem environment, with a fixed number of identifiable moves.” Chess also has the benefit of a “gold standard,” the so-called Elo rating, which allows for a relatively objective measure of player skill (Garry Kasparov has the highest Elo rating ever measured).
Looking at a database of 15,000 players at expert level or above, over 1.4 million games, the researchers looked at male and female players’ propensities to play risky or safe strategies. What they found was that even when controlling for age, Elo rating, and other variables, women were two percentage points more likely to play it safe than male players.
This may sound like a rather small difference, but small differences add up — over a career playing chess or over years of investing."
You can read the article at: http://www.smartmoney.com/investing/stocks/testerone-and-the-trading-floor/
He also has an atricle at:
http://trueslant.com/ryansager/2010/03/26/testosterone-and-the-trading-floor/

From the latter you can click on the PDF version of the study. I took the time to read it, thinking about the hours I spent recently going over the annotations of GM Judit Polgar in the 2010/1 New in Chess magazine to the Bishop's Opening game with GM Boris Gelfand, played at Kanty-Mansiysk last year. I began to play the Bishop's Opening after reading the preface to the Bowdler-Conway game, played in London in 1788, in the book 500 MASTER GAMES OF CHESS, by Tartakower and Du mont: The truth-as it was known in those far off days. Her annotations comprise six pages, about the same as my annotations to the game, and I mean MY annotations, because I have no Oracle. All together I figure I've spent a day of my life thinking about this beautiful attacking game.
I wonder about Judit while reading the study. She is certainly an anomaly when it comes to women players. She is not just an aggressive player FOR A FEMALE, but a naturally aggresive player for any human being! Then again, maybe that's the reason she is the strongest female chess player of all time.
I also wondered what the authors of the study mean when they write, "The lowest level required to obtain a Master title is a rating of 2300. Could that be a misprint?
In their Concluding Comments, the authors write:
In our introduction we sought to establish a link between the strategic thinking of highly
skilled chess players on the one hand, and the chances of successfully climbing the career
ladder on the other. There are innumerous situations where men and women compete, for
example in a negotiating situation, which might be characterized as a “two-person
competition,” as noted by Niederle and Vesterlund (2007). They show that compared to men
women avoid competitive schemes, and when forced to compete, they fail to do so
appropriately. Basically, our results are consistent with theirs; however, we add a new facet
by showing that men become more inclined to choose aggressive strategies when they face a
female opponent. One might read this result in terms of overconfidence. Some studies point at
men being more overconfident than women, especially in “male-dominated realms” such as
trading, see Barber and Odean (2001). Based on our results, male overconfidence might
become even stronger when men face a female opponent. Alternatively one might read the
results in terms of gender stereotyping, leading to the undervaluation of the real capacity of
women in cognitive demanding situations. The latter aspect might also explain why women
too are more prone to choosing aggressive (i.e. risky) strategies when playing against female
opponents who on objective grounds are stronger players."
I thought of this when reading the introduction to the book: The Predictioneer's Game: Using the Logic of Brazen Self-Interest to See and Shape the Future by Bruce Bueno de Mesquita.
He writes, "We live in a world in which billions-even trillions-of dollars are spent on preparations for war. Yet we spend hardly a penny on improving decision making to determine when or whether our weapons should be used, let alone how we can negotiate successfully. The result: we get bogged down in far-off places with little understanding of why we are there or how to advance our goals, and even less foresight into the road-blocks that will lie in our way. That is no way to run a twenty-first-century government when science can help us do so much better."
The last three Sectaries of State have all been women. It could be that it is a good thing, for the sake of mankind, to have women in a negotiating situation characterized as a "two-person competition."