Intended for healthcare professionals


Sex, aggression, and humour: responses to unicycling

BMJ 2007; 335 doi: (Published 20 December 2007) Cite this as: BMJ 2007;335:1320
  1. Sam Shuster, honorary consultant, emeritus professor of dermatology
  1. 1Department of Dermatology, Norfolk and Norwich University Hospital, Norwich NR4 7UY
  1. sam{at}

    Sam Shuster compares men and women’s responses to the sight of a unicyclist

    After retiring from a busy university department in Newcastle upon Tyne, and with the time and the need for more than the usual consultancies, I was able follow some of my more extreme inclinations. As a cyclist, I had occasionally thought of using more or fewer wheels, but it was only when choosing a grandson’s gift that I got seriously lost in contemplation of a gleaming chrome unicycle. My wife said “buy the bloody” thing, which I did on the whim of the moment. After months of practice at home, I graduated to back streets, a small paved park, and finally town roads. I couldn’t avoid being noticed; in turn, I couldn’t avoid observing the form that notice took. Because at the time there were no other unicyclists in the area, such sightings would have been exceptional, yet I soon found that the responses to them were stereotyped and predictable. I realised that this indicated an underlying biological phenomenon and set about its study.


    As I had no idea what the phenomenon was, my reservoir of multipurpose preconceptions could not provide a testable hypothesis; instead, I needed simply to observe neutrally the response to the unusual stimulus of unicycling administered reproducibly. I therefore wore the same bland tracksuit, trainers, and facial demeanour, and I rode “neutrally” with no attempt to entertain.

    I closely observed for just over a year, recording details of the responses and those who made them (estimated age; relationships; and class from dress, speech, and behaviour) as soon as possible. Subsequently, I only recorded new responses or significant variants. I collected written recordings from more than 400 people.


    Observed responses

    Less than 5% of people—mostly elderly men, women, and teenage girls—showed no reaction. About 1-2% of people expressed anger, distaste, or fear of collision, mostly elderly women and some men walking with sticks.

    More than 90% of people showed a physical response—from an exaggerated stare or acknowledgment to a wave, nod, smile, or a show of mock surprise and fear, which reflected any remarks made.

    Almost 50% of those encountered, more often men than women, responded verbally (box). The sex difference in the type of response was striking. Around 95% of responses from women praised, encouraged, or showed concern, and women made few comic or snide remarks. In contrast, only 25% of the comments made by men indicated praise, appreciation, or neutrality, whereas 75% were attempts at comedy, often snide and proffered combatively as a put-down. Equally striking was their repetitive nature, even though given as if original—almost 66% of these “comic” responses referred to the number of wheels (the most common), the absence of handlebars, or a part having being lost or stolen (box). Less than 25% used less obvious snide humour, but often with stylistic repetition. Some remarks were fired off as if they had been rehearsed on approach. More often, people paused briefly while trying to formulate the response, which was sometimes delivered after I had passed. This pause to find a comic phrase contrasted with the immediacy and apparent spontaneity of the few laudatory remarks made by men and the many made by women. Some of the remarks showed combativeness and envy, such as “bet I could do better than that.”

    Some verbal responses to unicycling

    Early years
    • Mother to son about 5 years old, “Oh look, why is he riding on one wheel?”

    • Mother to son in pram, “Isn’t that clever.” The boy repeated, “Clever”

    • Father to son about 3 years old, “Look his bike’s got only one wheel . . . wonder what happened to the other”

    • Man to daughter about 4 years old, “Look . . . he’s got no handle bars”

    • Boy of 3-4 years to mother, “Mummy the man’s broken his bike—it’s only got one wheel”

    Inquisitive 5-12 year olds
    • “Was it hard to learn?”

    • “Where do you buy them?”

    • “How much did it cost?”

    • “Why do you use only one wheel?”

    Aggressive boys
    • “Do you want to knock him over?” “Yes I bet I could do it”

    • While kicking a football, “Got a good target”

    • Riding at me on bicycle, “Fall off granddad”

    • Sudden loud shouts, then they threw small pebbles

    • Loud noises, then “You’re gonna fall off . . . you’re gonna fall off”

    • “You make it look so easy”

    • “You should dress up as Santa for the children”

    • “God that must be difficult”

    • “Well done.”

    • “Clever, clever”

    • “Wonderful . . . I am impressed”

    • “Magic . . . it is magic”

    • “You are an Olympic champion”

    • “I wish I could do that . . . Oh that looks good”

    • “That must need a wonderful balance”

    Wheels (minor variations of the first two were the most common)
    • “Lost your wheel?”

    • “Hey do you know you’ve only got one wheel?”

    • “I’ll look for your other wheel”

    • “Couldn’t you afford the other wheel?”

    Handle bars
    • “Do you know you’ve lost your handle bars?”

    • “Is it easier with nay handlebars?”

    Lost something
    • “Lost half your bike”

    • “Somebody’s pinched half his . . . ”

    • “There is a part missing isn’t there”

    • “Where’s the other bits then?”

    Circus and juggling
    • To tune of Entry of the Gladiators “Do you want music?”

    • “I didn’t know the circus was in town”

    • “Thought about joining a circus?”

    • “Forgotten your?” Mimed juggling

    Indirect put-downs
    • “You must like living dangerously”

    • “Odd things you find on cycles”

    • “And what were your other birthday presents?”

    • “Is it a new form of transport then?”

    • “I suppose it saves on tyres”

    • “You park your bike for two minutes and that’s what you are left with”

    Middle class men
    • “That’s unique”

    • “I’m envious . . . I couldn’t do that”

    • “That’s great . . . I wish I had a camera”

    • “That’s good”

    • “What a star you are”

    Elderly men
    • Arthritic man, “It’s quicker to walk”

    • Man moving poorly with effort, “I’m glad I don’t have to do that”

    • Arthritic man, “Better you than me . . . I wouldn’t even get up on it”

    • Two men walking together asked seriously, not as a joke, “Are you practising for a circus then?” and “Does it crush your bollocks mate?”

    Evolution of responses

    Young children usually showed curiosity, and drew their parents’ attention to the unicycle as often as the converse. Parental comments showed a sex difference—fathers’ remarks were either typical male (wheels, etc) or practical (maintaining balance, etc), whereas mothers’ comments praised and usually informed the children.

    Boys and girls of about 5-12 years usually showed interest. They often asked practical questions about learning, purchase, and so on (box).

    From about 11-13 years, boys began to develop an aggressive response, which continued throughout the school years. They tried to put me off balance by suddenly shouting, jumping out of hiding, kicking a football, throwing stones, or riding a bicycle at me; a few asked for a ride in addition to aggressive behaviour.

    A further change in male behaviour was seen during the late teens—aggression decreased, but they tried to make disparaging “jokes,” which were sometimes incorporated into mocking songs. This change continued, and finally evolved into adult male humour with its concealed aggression.

    The female response was subdued during puberty and late teens, with apparent indifference or minimal approval, such as a tentative smile. It then evolved to the laudatory and concerned adult female response. Rarely, a male “joke” was made by girls in male company.

    Miscellaneous observations

    Men who seemed to be of higher social class, older men, and the few Indian and Asian people encountered gave more approving and fewer comic responses. The response of people in cars was remarkable. Young men in old cars were very aggressive, acting as if to frighten me off the road—they lowered their windows and shouted abusively, waved their arms, and hooted. I did not see this with women drivers and older men in more expensive cars.


    This study observed the response to a sudden, unexpected exposure to a new phenomenon—unicycling. The response to this stimulus was surprisingly consistent but varied with age, sex, and stage of sexual development. Young children were curious, but as boys grew older their response became physically and verbally aggressive. As boys matured to men their response became more verbal and evolved into the concealed aggression of a humorous verbal put-down, which was lost with age. In contrast, the female response was praise and concern for safety.

    A strength of the study was that it involved the observation of an unexpected, spontaneous response, not a planned test of a preconception. Possible limitations are that the stimulus may have varied despite attempted consistency; but the main reservation is that because responses were not from a consecutive cohort or sample, the findings are only semi-quantitative. Fortunately, the differences found were large enough to overcome this; likewise the subjective assessments of relationships, age, and social class. Unicycles take one wheel and one person; confirmation by another rider, with a different style, appearance, dress, age, sex, and location is desirable, but the observed responses are still relevant to the situation studied

    Biological systems are often best defined by stimulation—for example, the heart by exercise—but conscious modification makes this less reliable for mental responses. Sudden exposure to a novel stimulus lessens the opportunity for this, and the unprepared response is more likely to reflect an underlying attitude. Opportunistic use of unicycling in this way was validated by the consistency of the response to it.

    The physical responses corresponded to the verbal ones, and added little to them. Most men clearly meant their responses to be funny and snide, and they were often given as a put-down. Women, however, usually responded with pleasure and admiration and were concerned about safety. The consistent content of the male “joke” and its triumphant delivery as if it was original and funny, even when it was neither, was remarkable, and it suggests a common underlying mechanism. The evolution of the response provides the clue to what this might be.

    Children showed curiosity and interest, which changed in young boys. In older boys, curiosity was replaced by minor physical and verbal aggression—attempts to topple the unicycle coupled with first attempts at simple, mocking humour. In teenage boys, the physical aggression was replaced by verbally aggressive mockery, with elements of adult humour. This response “matured” to its adult male form as a mocking joke, which partly disguised its aggressive origins, an origin that was again revealed by the gross response of motorists, in whom aggressive behaviour is often exacerbated. This adult stage corresponded to the peak of virility and ameliorated in older men, who were more neutral and amicable, with few attempts at a jovial put-down.

    The idea that unicycling is intrinsically funny cannot explain the findings—particularly their repetitiveness, evolution, and sex differences—and the notion that males are just expressing a greater sense of humour simply restates an observational fact. Social and ethnic differences seemed to soften the male response, and such a softening was also noted when unicycling in Framlingham, a small Suffolk town to which I had moved from Newcastle. A genetic effect would explain the sex difference, but not the waxing and waning of the male response—the simplest and most direct explanation is androgen induced virility. Such a causal association fits well with the observed evolution to aggression, an attribute related to androgens (figure[f1]), but direct endocrine confirmation would require studies not available to a unicyclist. The observed aggression could be a male response to confrontation, a situation where competition and combativeness are never far away. The male response to female unicyclists has yet to be studied, but the results of inquiries to unicyclists in other regions and countries suggest that the same jokes about wheels predominate.


    Estimated changes in serum testosterone concentrations in males with age

    Particularly interesting for the evolution of humour was the way the initial aggressive intent channelled the verbal response into a contrived but more subtle and sophisticated joke, in which aggression is concealed by wit. This shows how the aggression that leads to humour eventually becomes separated from it as wit, jokes, and other comic forms, which then take on an independent life of their own.

    These observations lead to the conclusion that humour evolves from androgen primed aggression. But can that conclusion be generalised? Repartee and banter have many of the characteristics of controlled aggression—so often revealed when control is lost—and it may be no coincidence that quick wit is likened to a rapier. The findings may also be relevant to the great male-female divide in humour—women tell fewer jokes than men and most comedians are men, despite some notable exceptions. The findings also suggest that the difference is sexual rather than social. I will not generalise into the many writings on humour—too many of which take an armchair view of the bedroom—from Freud on male humour as an aggressive response to women to the priapic interpretations of Roman sculptures and the effect of salacious comic cartoons on subsequent aggressive behaviour. The range of theoretical options on offer is too great and unproved for interpreting or extending a simple experimental study such as the response to unicycling.

    The existence of an overwhelming sex difference inevitably raises the possibility of biological advantage, in particular whether male humour enhances female sexual preference. Marty Feldman, a notoriously unprepossessing comic, had no doubt of it, and Diane Keaton said she was mostly won over by men who made her laugh. Darwin’s Descent of Man defined the dominant evolutionary role of sexual selection.1 The components of mate attraction are becoming defined2—the male woos and the female selects—and male humour seems to be involved.3 The present finding that humour may reflect androgen induced aggression could provide a Darwinian explanation both of its attraction and its continued use as a sexually useful tool.

    And the female response? Embryologically, the female is the fundamental body form from which the male develops. Could it be that without androgens the human response would be female, with its favourable, warm, tolerant concern? Perhaps male aggression is too high a price for humour.


    The response to the unexpected and novel stimulus of seeing a unicyclist was surprisingly consistent even to the words and gestures used, and these varied with age, sex, and stage of sexual development. In males the response moved from curiosity in childhood, to physical and verbal aggression in older boys; this became more verbal as the boys matured into men and evolved into the concealed aggression of a repetitive humorous verbal put-down, which was lost with age. In contrast, the female response was praise and concern for safety. These findings suggest that humour develops from aggression in response to male hormones.


    • Competing interests: None, apart from owning a bicycle as well as a unicycle.

    • Provenance and peer review: Not commissioned; externally peer reviewed.

    • This study arose from a chance observation that I extended for confirmation, and then for characterisation and analysis.


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