It’s a spectator sport that’s hugely popular in Japan, but little known elsewhere – perhaps because it’s so Japanese. That’s to say, odd to Western eyes. Even its fans admit it’s more mesmerising than entertaining.It’s been going only since 1952, but is held most days in 24 locations across Japan. These “stadiums” are built on lakes, rivers or the sea, with others on artificial concrete ponds in the midst of cities. The course is just a 600-metre-long oval.Each race consists of six boats going just three times round the course, and lasts less than two minutes. But they string it out by having a practice race, and then individual 150-metre time trials before the race.The boats are quite small, with a detachable engine. They get off to a flying start, with boats that jump the gun, or pass the starting line more than a second late, being disqualified.As you can see from YouTube, much of the skill comes from manoeuvring into the best position at the start. But being first round the first turn is also important, and usually means you’ll win. What we’d call sledging is another competitive tactic.All the boats are identical and owned by the stadium, being issued to each competitor for each race at random. Same with the engines. Each driver – all of them professional - gets a short time to tune their allotted engine for better performance. You’re allowed to supply your own spark plug, but that’s all.Drivers crouch down in the straight to give less resistance, but then stand up, using their body to slow the boat for the turn. They crowd so close together on the turns it’s amazing more of them don’t collide.Why do so many Japanese get so excited about all this? Sorry, didn’t I mention it? Speedboat racing is one of the few sports in Japan on which it’s legal to gamble.Extensive statistics are kept on the past performance of drivers, boats and engines to help the punter with their bets. All the race preliminaries are there to give the punters more information before they place their bets.But why would any this be of interest to economists? Well, as you may know, economists are great believers in competition, and are curious about how it works.In this case, however, there’s another attraction. Japanese speedboat racing involves competition between men and women. Better, competition between men and women in the same races, but also all-male and all-female races.There is great controversy over whether men and women are equally competitive or women are, in general, less competitive. And, if less competitive, whether this is innate or is learned behaviour.Many people’s answer to these questions is based on their beliefs (and some use social media to tear into those who say things than conflict with their beliefs) but these days, surprisingly, academic economists search forevidence to shed light on such controversies.Which means academic economists spend their days searching for good “data sets” of empirical information to which they can apply their statistical tests and reach conclusions about issues of interest.Guess what? In speedboat racing those meticulous Japanese have produced a fabulous data set with which to compare the competitive behaviour of men and women.The more so because, though men outnumber women by more than seven to one, they all receive their one-year training at the same college and are treated equally in the race, being randomly assigned to races. In mixed-sex races there’s usually one woman and five men.Such a “natural experiment” with real drivers competing professionally for big money is far more persuasive than some lab experiment where student volunteers compete for tiny amounts.Two economics professors, Alison Booth of the Australian National University, and Eiji Yamamura of Seinan Gakuin University in Japan, have examined more than 140,000 individuals’ racing records in a study.They found that women’s race times are slower in mixed-sex races than in all-women races, whereas men’s race times are faster in mixed-sex races than in men-only races.In mixed-sex races, they found that men were more aggressive – as shown by lane-changing – in spite of the risk of being penalised if they contravene the rules, whereas women followed less aggressive strategies.So the same woman performs relatively worse in mixed-sex races compared with single-sex races, while for the average male racer the opposite is true.This shows that female competitive performance – even for women who have chosen a competitive career and are very good at it – is enhanced by being in a single-sex environment rather than in a mixed-sex, in which they are a minority.But they found no difference between the genders on number of disqualifications. So while male racers do more lane-changing than females, the men are no more likely to be caught.“We suggest that gender-differences in risk attitudes and confidence may result in different responses to the competitive environment, and that gender-identity is also likely to play a role,” the authors say.According to the “gender-identity hypothesis”, a society’s prescriptions about appropriate models of behaviour for each gender might result in individuals experiencing a loss of identity should they deviate from the relevant code.The gender imbalance in mixed-sex races may trigger awareness of gender-identity for both men and women, and this may go some way to explaining each gender’s different behaviour in mixed-sex races to same-sex races.“For example, a man’s gender-identity may lead him to consider being defeated by women to be more dishonourable than by men, and he will try to avoid it,” the authors conclude.