Monday, July 28, 2008

More Testosterone!

Another interesting research paper on the relationship between testosterone and performance, this time in female rugby players:

Testosterone, cortisol, and women’s competition
Helen S. Bateupa, Alan Boothb, Elizabeth A. Shirtcliff, Douglas A. Grangerc
Evolution and Human Behavior 23 (2002) 181–192

Hormone (testosterone, cortisol)–behavior relationships have been extensively studied among male competitors, and far less so among female competitors. To address this gap, we studied members of a nationally recognized college women’s rugby team. Seventeen players (ages 18–22 years) provided saliva samples 24 h before, 20 min prior to, and immediately after five league matches. Subjects selfreported aggressiveness, team bonding, pregame mental state, postgame performance evaluation, and whether the opponent was more or less challenging than expected. Results revealed that both testosterone and cortisol levels increased in anticipation of the matches. Postgame levels of both hormones were higher than pregame levels. The pregame rise in testosterone was associated with team bonding, aggressiveness, and being focused, but was unrelated to perceptions of the opponent’s skill. Testosterone change during the game was unrelated to winning or losing, evaluations of personal performance, or perceptions of the opponent’s threat. Game changes in cortisol were positively related to player evaluations of whether the opponent was more of a challenge than expected, and negatively related to losing. These results are compared with hormone–behavior patterns found among male competitors and are interpreted within a recent theory of sex differences in response to challenges.

Selected bits I found interesting / possibly relevant to chess

1.1.1. Testosterone
In men, the relationship between testosterone and competition is reciprocal. Males characteristically experience a testosterone increase in anticipation of competition (Booth, Shelly, Mazur, Tharp, & Kittok, 1989). The precompetition rise is likely to make the individual more willing to take risks (Daltzman & Zuckerman, 1980), improve psychomotor function and coordination (Herrmann & Beach, 1976), and increase cognitive performance (Herrmann, McDonald, & Bozak, 1976; Klaiber, Broverman, Vogel, Abraham, & Cone, 1971; Vogel, Broverman, Klaiber, Abraham, & Cone, 1971). For a few hours following competition, testosterone is high for winners relative to losers (Booth et al., 1989; Elias, 1981; Mazur & Lamb, 1980). The rise in testosterone following a win is associated with positive mood (Booth et al., 1989), and is thought to be important because winners often face challenges from others soon after gaining new status.

1.1.2. Cortisol
(Cortisol is a steriodal hormone that the body produces in response to stress)
Another aspect of the cortisol– competition link is that top-seeded male tennis players exhibited consistently lower cortisol levels than did less talented players, suggesting that highly successful competitors may have above average ability at managing stress (Booth et al., 1989).

The pregame rise for testosterone and cortisol was similar for men and women, whereas the game rises in the two hormones tended to be higher in women than in men. This difference may be rooted in the fact that the primary source of both hormones is the same in women (the adrenal glands), whereas they differ for men. Among women, the process by which exertion and the challenge to status stimulate cortisol release may also increase testosterone production. The high correlation between cortisol and testosterone production among women during the game supports such an interpretation [r(49) =.46, P=.01].

Studies of male competitors indicate that a pregame rise in testosterone is related to performance. Among women, we found limited evidence of a link between the pregame rise and performance. The pregame testosterone increase was significantly correlated with reports of being focused just prior to the match [r(49) =.30, P=.03]. The link between estosterone and focus is consistent with prior studies as reported by Dabbs and Dabbs (2000, p. 45). Unlike men, the pregame testosterone increase among women was unrelated to perceptions of how easy or difficult the opponent was thought to be prior to the game.

Another way in which the rugby players differed from male competitors was that cortisol levels just prior to the game were unrelated to the rank or experience of the player. The more talented rugby players were just as stressed as less-talented teammates, suggesting that females may be more collective than individualistic in their expression of aggression.
Perhaps this suggests a reason women don't play chess-- the stress levels for skilled players do not decrease with experience in the same way that they do for male players? I remember watching a video interview with Rusa Goletiani in which she said she doesn't play so much because chess is so stressful.

The increase in women’s testosterone in response to a game was unrelated to winning or losing or to the evaluation of personal performance. Two factors were related to the cortisol rise during the game: (1) the extent to which the opposing team was more challenging than expected (something not studied in men) and (2) whether the team won or lost. Players who reported the opponent to be more challenging than expected experienced a mean rise in cortisol of 46 percentage points. When the opponent played at the level of skill expected, cortisol rose by 26 percentage points, whereas it increased by only 8 percentage points when the opponent was not as challenging as expected. In short, the greater the challenge experienced by the players during the game, the greater the increase in cortisol levels
[F(49) = 4.378, P=.04]. When the team lost, cortisol levels rose 0.34 mg/dl, whereas they only increased by 0.14 mg/dl if they won [F(49) = 3.973, P=.03]. The latter finding differs from those in studies of men. Elias (1981) found that, compared to losers, winners’ cortisol increased. Booth et al. (1989) found no relationship between cortisol change during the game and winning and losing.

Another possible disincentive for women-- testosterone levels (which are connected to a feeling of happiness) do not rise when females win? That seems both surprising and very sad to me? I don't understand at all why men would get more stressed when they win than when they lose? The authors make a bizarre suggestion that cortisol levels drop in women after victory so they can befriend their opponents, who they might play on all-star teams with?
(the following paragraph is quoted out of order to illustrate and explain my point)
(Also of interest is the observation that following a win the rugby players did not experience the testosterone-related elevation in positive evaluations of performance often observed in male competitors. Nor did the losers experience the decline in testosterone experienced by men. Rather, women who won experienced a very modest increase in cortisol compared to a relatively large increase among those who lost. These findings are consistent with Taylor et al. (2000) suggestion that females’ responses to challenges are more likely to be directed toward creating and maintaining relationships. Competition, especially that which is physically aggressive, has the potential to threaten old relationships and prevent the creation of new ones. Lower cortisol associated with winning suggests that females are managing the challenge of competition effectively so that high cortisol levels do not interfere with the conciliatory behavior that restores potentially beneficial relationships with individuals who were opponents a few moments earlier and teammates who were challenged in the heat of the competition. These women may very well be on the same team in all-star games; under such circumstances, they could not carry over animosity from earlier games in which they had been opponents.)

Men and women also share a precompetition rise in cortisol, but its bearing on performance is unclear. There are several differences. For one, men’s pregame cortisol is related to skill and experience—more talented competitors have lower cortisol (perhaps related to more effective stress management) than less-skilled men, something not found in women. Furthermore, men and women differ in their hormonal response to winning and losing. Many, but not all, male winners experience an increase in testosterone (correlated with elevation in positive evaluations of performance), while losers show a decline in the hormone. While women experience a rise in testosterone during competition that is greater than men’s, it is unrelated to either self-evaluation of performance, or winning and losing. On the other hand, changes in cortisol are related to the outcome of the contest: female winners have lower cortisol than do losers, something that does not occur among men.

It is possible that team participation rather than sex differences in biobehavioral response to stress are the key to understanding our results. It is important to keep in mind that the majority of hormone–competition studies involve sports that stress individual performance (e.g., tennis, judo, wrestling, racket ball, chess) more than team efforts. In a team, an individual’s status may be more strongly tied to the social interaction within the group than to the outcome of a particular contest. One-on-one competition may have a more direct impact on individual status and, therefore, on the testosterone response to winning and losing. Further studies of team sports will clarify this caveat.

It's a shame that there is no measure of the predictive link between testosterone levels and winning, but I guess in team sports this would not be statistically easy?
In other news, I just bought the board game Cranium and played a quarter of a game with my friend Nina (she had to go).


Unknown said...

i always wonder about the whole hormone thing with sports, it seems so complicated I prefer to just ignore it. to be honest, as long as people aren't taking hormones then lets just let nature sort it out.

Anonymous said...

Given recent developments perhaps someone should investigate the predictive link between testosterone levels and the likelihood of posting in the comments section of your blog. Just saying.


Greg Shahade said...

you cant play Cranium with just one player! Also note that I'm going to order High Society and Citadel.

Anonymous said...

Female rugby players ? Isn't that preselecting for high levels of something. I would like to see the study replicated in a less manly sport.

Anonymous said...

Interesting study.

I know lots of girls who can kick the crap out of me both physically and over a chess board; it always makes me smile with disbelief when I read something that states men are predisposed to be better for this chemical reason or that.

Davy Do

Our Sword said...

Are you SURE this is a chess blog? LOL

Greg Shahade, I think Cranium works best with husband/wife boyfriend/girlfriend combinations with some family thrown in. Makes for some superb shouting matches and "I'm not talking to you!" moments! ;-p

Anonymous said...

wtf i need more lizzy blog to read grrr...

Anonymous said...

We want some reports from Dallas!!!

I see you took 2 byes in the 6-day schedule.

Good Luck

Chess Guy

Elizabeth Vicary said...

sorry everyone--I miss you guys too, but its hard to think when i'm at a tournament. plus i'm supposed to write something for jenn first. so probably nothing for at least a week, but uscl season is coming soon, and I'll make up for it then...