What is the role of testosterone in videogame play? And how has it affected the way videogames are made?

The chemical testosterone is often considered a “sex hormone”, because of its role in sexual development in men, but in fact this steroid has behavioural effects on men and women that are substantially the same. Although men secrete about fifty times as much testosterone as women, women are substantially more sensitive to the hormone with the net result that similar behavioural effects can be detected among people of either gender. What's more, these effects can be found in essentially all the vertebrate species – fish, amphibians, lizards, mammals and birds.

Testosterone is an “action hormone”, that prompts quick responses and resolute persistence, not to mention stubbornness. Studies by various researchers, including John Archer, Andrew and Rogers, and James McBride Dabbs, have shown that animals and people who are high in testosterone can sustain a narrow focus for longer, and are thus persistent at the tasks they pursue. Conversely, low-testosterone people have been shown to be generally more friendly, more intellectual and more compassionate than their high-testosterone counterparts. As a result, low-testosterone people tend to do better in school, have higher paid (and higher status) jobs, have closer relationships with their families, and sustain happier marriages.

Another significant effect of testosterone is developmental: the higher dosages of testosterone result in greater brain volume in men but at the cost of a smaller corpus callosum, an area of the brain which co-ordinates information between the two hemispheres. (Note, however, that a larger brain does not make one smarter – despite what the Saturday morning cartoons might suggest). Researchers have observed that, typically, the female brain is far better at thinking in terms of networks (social or otherwise), although it should be noted that there is a great deal of variation among individuals. This change in brain development is a genuine gender distinction, and results from the effects of the higher levels of testosterone on developing boys.

A convenient way of summarising the effects of testosterone on behaviour is to suggest that high testosterone is correlated with dominance behaviours. This can mean many different things, including assertion, vanity, aggression, charisma, and high sex drive, but note that these behaviours can happen in people irrespective of their testosterone levels. It is not that testosterone causes dominance behaviour, just that it encourages it. High levels of testosterone are correlated with both roguish behaviour and heroism – Dabbs describes many examples of heroic behaviour among people with above-average testosterone, including fire-fighters and soldiers who acted to save the lives of others without any thought for their own safety.

In the context of play, testosterone has an effect in any competitive situation. Just before a tennis match, a professional player's testosterone will increase – and it will surge if they win a tournament. If they lose, their testosterone will fall. These changes in testosterone level are not restricted to physical sports, either – the testosterone levels of chess players also fall when they lose a game. Whenever an individual is emotionally invested in an outcome – when their pride is at stake, if you will, a drop in testosterone is likely in defeat or failure, and a spike in victory.

A recent study lead by David Geary at the University of Missouri in Columbia explored testosterone in the context of videogame play, specifically multiplayer Unreal Tournament 2004. Fourteen groups of three male players (who had not met each other before) were matched against each other after having practices together for about six hours. To add an incentive to win, the teams that were victorious earned a reward of $45, three times what the losers were paid for their participation.

The study found an unexpected effect: while winning players did experience a testosterone spike when they were victorious (and especially among players who had most contributed to the win), when the teams played against each other the highest scoring player tended to produce less testosterone than their defeated team mates. Similar results were found in a study by John Wagner of competitive domino players on the island of Dominica. When playing with people in their own village, winners testosterone levels fell and stayed low, whereas loser's testosterone fell then rebounded. Only when playing against people from other villages did testosterone reliable rise.

Testosterone can thus be seen as a driving force towards winning – rising in preparation for a challenge, and falling in defeat. But in a friendly contest between colleagues, the stakes are lower and testosterone has a significantly reduced role. One can assume that all forms of non-competitive play are less affected by testosterone, and indeed studies of pathological gamblers did not find a correlation with testosterone levels.

The results of the BrainHex survey, which is currently going on at BrainHex.com, reveals an interesting split in the play patterns of male and female players that may also relate to testosterone. Six of the seven play styles in this model have roughly the same distribution among men and women, and appear in the same order. Only one play style is significantly different by gender: Conqueror. This adversarial, victory-focussed style of play is the most popular among male players surveyed so far, being the highest rated in over a quarter of male respondents. But among female players in the survey, it ranks fourth (after Mastermind, Seeker and Achiever) with just one in eight female players preferring this play style above all others. (See the full numbers in the piece on BrainHex Class and Gender).

There is a significant gender skew in the respondents to the survey thus for, with just 11% female people in the sample: if a projection is made of how the audience would be comprised if it were made up of an equal number of male and female players, Conqueror would be third in the list, corresponding to one in five people. Seeker would be above it with just a few percent more respondents, and Mastermind at the top, corresponding to about one in four people. Exploration and problem-solving could well be more popular than striving for victory, although regardless of this all three play styles together still only represent two thirds of the players in the audience as a whole.

There are at least two distinct ways of looking at this data. Firstly, one could look at the industry's predilection for first person shooters and other competitive action games – all of which embody testosterone's focus on acting-over-thinking, and a persistent drive towards eventual victory – as more than adequately servicing the needs of testosterone in the audience for games. This naturally involves more male than female players (and it would be interesting to see if the female players who test as Conqueror in BrainHex would have above-average testosterone levels).

Alternatively, you could look at the popularity of Mastermind and Seeker among both men and women and accuse the industry of biasing its output heavily towards testosterone-style play, irrespective of the commercial reality of the marketplace. It is presumably no coincidence that the vast majority of people who work in the videogames industry are male, and thus far only Nintendo among the major platform holders has been able to push beyond thinking primarily in terms of Conqueror as the supreme element in videogame play.

There is a major unanswered question here. Is the market inundated with action games because testosterone-driven play is more addictive and satisfying than other kinds of play (and thus this is the most reliable audience to court) or is the prevalence of the 3D shooter merely the evidence that the industry has allowed itself to be biased towards making the games it wants to play, rather than exploring what the audience might want to play, as I have frequently accused?

The phenomenal success of games such as The Sims, Nintendogs, Brain Training and Wii Fit (all of which have sold more than twice as many units as the most successful first person shooter) suggests the latter, but it must be noted that among male respondents in the BrainHex survey 51% have Conqueror as either their first or their second highest ranked class, and even among female respondents 32% have Conqueror as the first or second highest. (Note that Mastermind appears as one of the top two classes for 40% of male and 50% of female, and Seeker appears as one of the top two classes for 34% of male and 45% of female respondents in the current sample).

What is happening in the videogames industry at the moment, principally via the work of Nintendo and casual games developers such as PopCap and Big Fish, is the realisation that there are other audiences out there just waiting to be tapped. What's more, these wider audiences for games can be reached via games that are a lot less expensive to develop than Halo 3 or Call of Duty 4, which cost around $30 million to develop and courted an audience of around 10 million players. Animal Crossing – which is proving to be a very popular franchise among the Mastermind players in the survey – sold as many units on less than a tenth of the development budget.

There will always be a thriving market for violent action games that demand quick thinking, swift reflexes and cut-throat tactics – undoubtedly teenage boys, adult men and some small percentage of women will continue to play and enjoy these kinds of games. But it's time for the industry to recognise that these games are not the most successful genres in production, and in fact that most of the games that go into the FPS marketplace fail miserably. Halo and Call of Duty, the flagship franchises for testosterone play, soak up the vast majority of the audience for 3D shooters accounting for roughly 50% of the sales of FPS games. In the last three years, the next highest selling FPS that wasn't in either franchise sold less than a third as many copies, while at least 2 in 3 first person shooters released over the same period failed to make back their development costs.

Does it really make sense for most developers to be making games to compete against vast numbers of better funded, better marketed 3D shooters with vanishing hope of commercial success? Or is this just testosterone dictating that the fight against incredible odds is a challenge that must be accepted? If games developers and publishers are wrapped up in some bizarre dominance struggle centred around shooting games it would mean that testosterone isn't just responsible for one of the more popular forms of play, it's also partly responsible for blocking the creation of videogames for a wider audience.