By Christian Jarrett

The effect of playing sport on men’s testosterone levels is well documented. Generally speaking, the winner enjoys a testosterone boost, while the loser experiences the opposite (though far less studied, competition unsurprisingly also affects women’s hormonal levels, though not in the same ways as men’s). The evolutionary-based explanation for the hormonal effects seen in men is that the winner’s testosterone rise acts to increase their aggression and the likelihood that they will seek out more contests, while the loser skulks off to lick their wounds. When it comes to vicarious effects of competition on men’s testosterone, however, the findings are more mixed. There’s some evidence that male sports fans show testosterone gains after seeing their teams win, but other studies have failed to replicate this finding.

A new, small study in Human Nature adds to this literature by examining the hormonal changes (testosterone and cortisol) in fathers watching their children play a football game – a situation in which you might particularly expect to see vicarious hormonal effects since it’s the men’s own kin who are involved.

The eighteen participating fathers (average age 47) were recruited in the US state of New Mexico where they were watching their kids (average age 13) play in a local football (soccer) tournament. Nine of them were watching their sons play, the others were watching their daughters. The dads provided saliva samples before and after the matches, and also answered some questions about their child and the game.

Anthropologist Louis Alvarado at the University at Albany and his colleagues, including the psychologists Melissa Eaton and Melissa Thompson at the University of New Mexico, found that the fathers’ testosterone and cortisol levels increased after the experience of watching the games (by 81 per cent and 417 per cent, respectively). These changes weren’t linked to the outcomes of the games, but were to an extent explained by whether or not the fathers believed that the referee had acted unfairly towards their child’s team – if they did perceive unfairness, the fathers’ post-match cortisol and testosterone tended to be higher (fathers with higher pre-match testosterone were also more likely to perceive unfairness).

The researchers said this main result of a link between hormonal changes and fairness perception was “consistent with a functional explanation in which hormonal changes are associated with the potential for future conflict – here, in the context of responding to potential threats affecting one’s own status and that of kin.”

Given that aggression among parents watching their kids has become “an important cultural issue”, the researchers added that their results could “… have implications for the growing body of literature that attempts to curb the problem of sideline violence by identifying the proximate and individualistic factors associated with conflict potential.”

Other findings to come out of the study were that fathers watching their sons showed greater testosterone rises than fathers watching their daughters, as did fathers who felt sports were less important to their child (this latter result was opposite to expectations, and the researchers speculated that it was perhaps connected to the fathers’ frustration or disappointment that their child was not taking the competition seriously enough).

A more technical finding was that gains in the fathers’ “stress hormone” cortisol tended to predict subsequent increases in their testosterone. This result provides tentative support for the so-called “positive coregulation” model of cortisol and testosterone, in which increases in cortisol supplement the effects of testosterone when males are competing, while arguing against the opposite theory that sees cortisol as down-regulating testosterone and reducing the likelihood of the individual engaging in competitive behaviour in times of stress. The researchers said the “positive coregulation” model makes more sense in evolutionary terms, with stress (and cortisol) priming high-ranking male primates to be more competitive when they are faced with the threat of status competition from more junior males.

—Steroid Hormone Reactivity in Fathers Watching Their Children Compete

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest