To expand on the findings of a previous post on shorter guys dominating the pretty boy and hip hop niches, itself inspired by a discussion at Steve Sailer's blog on short guys dominating the rockstar niche, let's now consider the average height of males who specialize in another show-off niche: daredevils. Since performing physically dangerous stunts must require a certain degree of athleticism, you might think that daredevils would tend to be taller than average, as in basketball, football, and other popular sports. On the other hand, perhaps what counts more than height or dominance are nimbleness, ability to maintain one's balance, and being a smaller target (e.g., when being charged by a bull or having darts thrown at one's body). To investigate, let's have a look at the heights of the main cast of the popular MTV daredevil show Jackass. [1] Examining just the hardcore, professional members:

Jason Acuña - 4'7
Bam Margera - 5'8
Chris Pontius - 5'8
Preston Lacy - 5'8
Ryan Dunn - 5'9
Brandon Dicamillo - 5'9
Steve-O - 5'10
Dave England - 5'10
Johnny Knoxville - 6'0.5
Ehren McGhehey - 6'1

Using the data at the excellent celebheights.com website, I could only verify the heights of Knoxville, Margera, and Steve-O (in the thread on Knoxville). The other heights are from their imdb.com entries, and so are probably exaggerated by 1 inch or so (this is clear from comparing cast members when they stand side-by-side in stunts). Making no adjustments, and leaving aside the outlier of Jason "Wee Man" Acuña (a "little person"), the mean here is 5'9.7; while reducing the unverifiable heights each by 1 inch gives a mean of 5'9.1. For American males age 20-39 (see the PDF here, p.10), mean height is 5'9.6, based on a sample of 1441. I assume the SD for height of the general population is 3 in., though the test is not affected by any reasonable choice. We accept the null hypothesis of no difference in means between daredevils and a random sample of males, regardless of whether we use the unadjusted or adjusted data (both p greater than 0.6 using a two-tailed t-test). Even norming to non-Hispanic White height does not make the results significant (p ~ 0.3). Admittedly the n is small, and perhaps a larger dataset on professional daredevils would resolve the issue of whether there truly is no difference or whether the non-significant trend toward shorter stature here is actually significant.

Looking at a related group of elite athletes in "extreme sports" such as skateboarding and BMX (rather than the all-purpose daredevils of Jackass), I found this handy webpage for a star-studded event that includes height info. NB: Tony Hawk is actually ~6'2, not 6'3 as reported at the above website (let alone the claim of 6'4 at imdb.com), according to several profiles (e.g., this one and this one), and by comparing him and Johnny Knoxville when they stand side-by-side in a stunt for Jackass Number Two. It's always safer to round down when we're talking about self-reported male height. Comparing the mean of these 15 males -- 5'9.3 -- with that of the aforementioned representative sample of American males, we again accept the null hypothesis of no difference in means (p greater than 0.7 using a two-tailed t-test). As with the stunts of "well-rounded" daredevils, those of the specialists too do not appear to demand taller or shorter than average height.

So, if daredevils tend to be of average height, why the insinuation in the title of the post that they qualify as "shorties?" In the mating arena, the minimum height for an American male to qualify as a "good blind date" is probably 6' or 6'1, so that men who are shorter than this must make up for it somehow. For example, a study of online dating outcomes (PDF) suggested that a 5'10 male would have to earn $32,000 more than a man of 6' in order to receive the same amount of attention from women. The idea is that females are more concerned with quality than quantity of mates, so that they focus on traits as proxies for quality. Since it's rare to find a male who scores highly on all desirable traits, most women face a trade-off between competing "almost dream guys."

Being a professional daredevil is a pretty easy way to signal your genetic quality -- only the truly blessed can perform one dangerous stunt after another without being disfigured, mamed, paralyzed, or killed (watch the bloopers reel for amateur daredevils and see). You need at least general intelligence, boldness and risk-taking, and physical deftness / coordination. So, this could be another instance of the Handicap Principle. Once the first few daredevils in history figured out that they could impress girls as sex symbols, they would have had more children than the population average, increasing the frequency of alleles implicated in the relevant traits. This logistic growth would have continued until their niche became saturated (i.e., when it would pay off more to specialize in some other niche than join the daredevils). Again, it's hard to attention-whore when everyone is exhibitionistic in the same way. [2] This show-off quality is what distinguishes the daredevil niche from others that might also preserve variation in daredevil-ish traits, such as that of young soldiers (cannon fodder). By hypothesis, daredevils are more narcissistic than soldiers.

These processes will maintain genetic variation in traits such as excitement-seeking and height when other pressures might want to erode such variation; e.g., females might in general want a 6' partner or a cautious father of her children. In the comments of a related post on the heights of female sex symbols, Jason asked whether the trend toward shorter male height was an effect of production companies wanting to minimize the height difference between male and female stars, preventing awkward shots. The data on daredevils suggests that this is not a reason, as they rarely appear kissing females on film, and the same is true of rockstars.

And returning to another post on the role of technology in preserving variation, new technology will help people to identify who is cut out to be a daredevil since most stunts involve taking punishment from some product of human artifice, taunting but escaping from a deadly predator using technology, and in general using technology to push the limits of human performance. Now, this is not to say that pre-industrial individuals were jumping off cliffs with a parachute, but the Spanish matador requires only a sword (and really a stick with a large, sharp arrowhead might do). Also, Jackass members Chris Pontius and Steve-O developed their own daredevil show, Wildboyz, in which they often don't use technology at all, but rely on withstanding assults from wild animals (e.g., having their buttocks stung repeatedly by scorpions or surviving a swim with killer sharks). So, there's no reason this dynamic could not have started tens of thousands of years ago, although surely recent history, during which human beings have radiated into a myriad of diverse physical and social environments, will have created different frequencies of such traits between populations. [3]

We now turn to the question of whether daredevils actually do manage to mate with top-choice females, since status per se isn't attractive (as Half-Sigma likes to point out w.r.t. World of Warcraft nerds). Here are some photos of the girlfriends / wives of the sub-6' daredevils:

Bam Margera's wife
Bam Margera's former fiance
Chris Pontius' wife
One of Steve-O's girlfriends (others)
Best example: Wee Man's girlfriend (see pics "w/ Trisha")
Dave England's wife
Dave Mirra's wife (in the middle)
Carey Hart's wife is singer Pink
Bucky Lasek's wife

Perhaps more important than quality is quantity of mates, since the latter is more of a limiting factor on male reproductive success. Steve-O says here that he often sleeps with groupies, and judging from the friends on the MySpace pages of the Jackass members, their groupies are plenty -- and plenty attractive. On a final note, the shorter male readers should take this into account when encouraging your sons to take up one activity or another: if you want them to be successful with females, they'd better train hard to enter a niche that's tailored to short or average-height guys.

[1] No student of human biodiversity can forever avoid pop culture icons, filled as their ranks are with freaks and deviants of all kinds. The only DVD I've ever bought is Jackass Number Two, which I highly recommend to all the young male readers, if you haven't seen it already. The DVD contains lots of bonus footage, too. It is easily one of the most hilarious movies I've ever seen. For those who are unfamiliar with the material, here are a few illustrative examples from YouTube (both NSFW): here and here.

[2] Another clear example of the exhibitionistic appeal of the Jackass members is that they frequently engage in very homoerotic behavior, although none are gay. This is like the increasingly large group of straight girls in college (and, I hate to think, high school) who conspicuously make out with each other at parties (leks) in order to monopolize the attention of the alpha males.

[3] One puzzle is why sub-Saharan Africans are not only underrepresented among daredevils, but are positively freaked out as a group by the idea. (Watch any black stand-up comic show long enough, and soon you'll learn that they love to joke about how insanely death-defying White people can be, in contrast to the sensible Blacks. Another frequent topic is that White people stick around to find out what's going on in a calamitous situation, whereas Blacks immediately get the hell out of there.) This is a puzzle because they are well represented in most other show-off niches such as dancers, singers, athletes, models, and so on. Two possible reasons for this are the aforementioned aversion to "danger in nature," as well as their group's mean IQ of 85. Again, part of the daredevil appeal is that you rely on smarts to avoid accidents. Linda Gottfredson recently argued that avoidance of accidents was part of the reason why human beings became more intelligent (her first paper under 2007). The Jackass members are smart enough to pass high school-level classes at least (though Chris Pontius dropped out); Steve-O attended the University of Miami for a time, and his father is a high-ranking business executive.

Labels: babes and hunks, height, maintenance of variation