Below I'm asking and answering the questions. Yes, it's highly contrived, but I think this is the easiest way for me to address the questions that commonly come up when people hear about my work. Please go ahead and ask more questions and share your observations.
Thanks for your interest,
You can download the paper that came out yesterday here:
What do you mean by "more men run relatively fast"?
RD: I mean that you if count up how many men and how many women run within say 5%, 10%, or 25% of the men's or women's world record, you'll almost always find that a greater number of men than women achieve that standard. Usually it's about three times as many men that run relatively fast. In this recent paper I did with Don Mitchell we studied over 300 road races in the U.S. Our focus was non-elite runners so we used the 25% standard. This comes out to 16:15 for men and 18:27 for women.
How widespread is the pattern of more men (and boys) running relatively fast than women (and girls)?
RD: We've shown that his pattern occurs within almost any population of U.S. runners, from high school runners in one of the 50 states, to a local road race, to the end of year top 40 American performances lists, Obviously, there will occassionally be exceptions, especially at races with a few hundred participants or fewer.
Could this relative performance phenomenon be due to most of the women's world records being somehow exceptional? I mean, everyone knows that Radcliffe's marathon world record is simply incredible.
RD: Yes, truly exceptional world records could potentially throw of our results a bit. So when we do our analyses we usually use the average time of the top 10 performances of all time, only allowing one performance per individual. We call this the 10-fastest standard. So Paula's 2:15:25 counts as one of those but her other performances don't. In our recent study, the 10-fastest standard for the marathon was 2:04:50 for men and 2:19:11 for women. Those numbers were current in January 2010, when we did most of the analyses. Obviously, the men's best times have improved in 2011, but we've shown in this paper and other ones, that these slight changes, such as the 10-fastest standards being a percent or two faster or slower, don't affect the overall results.
So it seems like you're penalizing all these female runners because there are a smaller number of women who are exceptionally fast. That doesn't seem fair, does it?
RD: Yeah, one way of looking at this is "wow - the best women really are very far ahead of the other women." But that's not the whole story. Even in non-elite populations, such as the top 40 runners at a state cross-country championship race, the boys are reliably bunched more closely together than the girls are. We showed this in one of the papers published in 2006. It really is the case that, for males, it is more crowded at the top.
Okay, so if there are more relativey fast males than relatively fast females, why do you think this has something to do with motivation to train?
RD: Let me begin by saying that there are lots of possible reaons why there might be more relatively fast males. For instance, an easy explanation would be that more males are running in the first place. This was true 30 years ago but it's mostly not true anymore because there's no sex difference in colllegiate and road race participation and males only participate slighly more in high school, not nearly enough to explain the threefold difference in relatively fast performances. Another possible explanation is that females suffer higher injury rates so fewer can do the kind of training really needed to excel in distance running. This would make sense in sports like soccer and basketball where injury rates are much higher for females, but it doesn't seem to work for running. When researchers compare male and female runners within similar backgrounds there are no differences in injuries. The motivation to train explanation seems to work, however. Males do report somewhat higher training volumes, in terms of mileage and duration, and cross-sectional studies indicate that when men and women do the same kinds of training, say 100km/week, they show similar relative performances on average. Now I must add that this conclusion is preliminary - this is what current research suggests, but more research should be done. It's also possible that there could be more than on explanation that is correct - it might be part motivation and it might be partly something else.
But you're saying that, as far as you can tell, male runners are truly dedicated in their training but female runners are not?
RD: No, I'm not saying that. First, of all the many runners, male and female, who run in road races and participate in high school cross country, very few are training in a way that is really going to optimize their performance. And most of them know that. They're running for lots of reasons, and competition simply isn't high up on the list. What I'm suggesting is that the small percentage of men who are training to truly optimize performance over the long-term is about 3 times as large as the small percentage of women who are doing so. Maybe it's 3% of all male runners and 1% of all female runners. Obviously different people have different definitions of what truly dedicated training involves, so these percentages are just for illustration.
So you're not saying that elite female runners aren't as dedicated in their training as the elite male runners are?
RD: Right, I'm not saying that. My impression, and the studies I've read, indicate that elite males and elite females, train very similarly. What I am suggesting is that the pool of males who are desperately trying to make it to that elite level is larger than the pool of females who are trying to do so. An analogy would be to compare a top 10 finisher in a Canadian national meet to a top 10 finisher in an American national meet. Obvioulsy both would be highly talented, highly dedicated runners. But nobody would deny that, in general, there is going to be more depth in the American meet.
So why do you think there might be more male runners truly dedicted to their training?
RD: We're getting into sexual selection and some other challenging topics, so I'd suggest consulting some of the papers I cite in our paper! But the short answer is that men may have a stronger drive than women to compete for status because status has been more crucial for male reproductive success during human evolutionary history. There are many ways to compete for status, of course. These include excelling in science or the arts, being a clever politician, physically intimidating rivals, or earning (or stealing) lots of money. Sports is another possible domain to achieve status and my reading of the evidence is that, on average, males are substantially more interested in doing this. Obviously the particular area where someone attempts to gain status will depend on their talents and their opportunities. But this difference in sports interest even seems to hold true in the modern U.S., where we've undeniably made substantial progress in equalizing sports opportunities for males and females. I realize this hypothesis is still speculative and I am doing more research to test it.