More stable but potentially less profitable. Las Vegas is well aware of this study, previous to its existence...certainly poker players are aware of it.

In poker terms I would liken older men and women with high cortisol to tight passive poker players...they are unimaginative and scared to maximize value on the hands that they do play, they don't push to full value without a near lock on absolute certainty. Meanwhile traders or poker players who are simply and flat out over/loose aggressive(typically asians, blacks and hawain shirt types) are constantly getting themselves in trouble because they win by tossing all criteria out the door and engage in incredible acts of immagination. "Ideal" poker is something of mean between these extremes: tight or selective aggressive, not so tight that one is locked into a conversation about the possibility of crossing the same river once or twice, for as Aristotle notes such people are vegetables...and yet not so immaginative/aggressive as to presume that the river will yield to your will if you whip it. Tight aggressive poker...it sounds so easy, even a caveman could do it as Geico might say, and yet few things are as unatural to us as this disposition.

The determinism isn't primarily testosterone based...which is why taking steroids would be a joke, rather the boosts is similar to what poker players call a hot streak...a zone you can get into where nothing you do is wrong, at some point in this streak you begin to assume that you are Xerxes...and this is where you become loose aggressive...you develop habits that cannot be sustained over the long haul...habits that are mathmatically incorrect, that do not have positive expectations. Of course he notes that if traders could keep the hot streak going for a year they would make a million dollars more on average...if I could keep my modest hot streaks going I could make a million dollars a year playing poker at much smaller stakes...yet obviously the principle of Mike Caro is applicable here: money not lost is money won. It is actually bad to win in a fashion that is not rational.

The answer is traders who have a well developed grasp of fundamentals, people like Warren Buffet who nevertheless have a sort of philosophic bent to them(read his annual newletters for a good riot), that allows them the proper relation towards "certainty", the ability to call a bluff(or the emporer) naked if need be. If Warren Buffet can find a discrepency or a small edge somewhere he pushes it to the max. He is among traders what is among poker players the highest ideal:tight/selective aggressive play.

Warren Buffet is able to achieve this in part by not letting himself get carried away Xerxes style by his own wealth, and grounds himself emotionally in what he calls the mid-western sensibilities and the virtues of Ben Franklin.

One problem with such conclusions is that people make cause and effect statements from correlational data. That is to say, it is possible that increases in testosterone caused these traders to make more money. However, and just as likely, an increase in profits caused a subsequent spike in testosterone levels. While the researchers tried to control this by measuring testosterone levels in the morning (before trading began), this is still a correlational design. A correlation simply tells one that two variables (in this case money earned and hormone levels) are related, but doesn't tell you whether one variable caused the other to change.

This is the same flaw in Al Gore's argument that an increase in CO2 emissions is causing an increase in the earths temperature. This may, or may not, be true. It is also possible (and data suggests) that an increase in global temperature (caused by changes in solar activity) causes a subsequent increase in CO2 levels. This, of course, is quite different than what global warming alarmists would have one believe.