Evolutionary perspectives on sport and competition
Abstract and Keywords
This chapter examines the theoretical and empirical research into evolutionary aspects of four complex issues of human behaviour in sports. We highlight how evolutionary approaches have promoted our understanding of human sports and competition. To begin with, we describe the relationship between sports competitions and testosterone levels and elucidate how winning and losing leads to different, sometimes status-changing, endocrine responses. Secondly, we look at ‘home advantage’ and examine how hormonal and psychological research has aided our understanding of this well-known phenomenon. The next section focuses on possible evolutionary explanations as to why left-handers may have an advantage in physical combat in both traditional and westernized societies. The final section examines colour influences on human behaviour in general and on sports competition in particular, focusing specifically on the significance of the colour red in human competitive interactions. These four themes serve to highlight the value of evolutionary approaches in enhancing and enriching our understanding of human sports competitions.
Sports are ubiquitous in human cultures and are valued as a form of physical competition (Chick and Loy 2001; Llaurens et al. 2009a). At the same time, watching sport is a pastime that captivates viewers across the world, with major sporting events such as the FIFA World Cup or Olympic Games attracting audiences of hundreds of millions, both as live spectators, and as television, Internet, and radio viewers or listeners. The worldwide appeal of sports such as football has led economists and psychologists to devote an increasing body of research to this global phenomenon (Kocher and Sutter 2010). Recently, there has also been a dramatic increase in research examining sport from an evolutionary perspective.
This chapter describes research into evolutionary aspects of human behaviour in sports, illustrating how evolutionary insights have been applied and have enriched our understanding of human sports and competition, and points to promising ideas for further study. We focus on four issues that have received recent attention. First, we describe the relationship between testosterone levels and sporting outcomes and how they play an important role in the phenomenon of home advantage. Second, we explore the issue of home advantage and its psychological and hormonal mediators in more detail. Third, we elucidate possible explanations for why left-handedness may be advantageous in physical combats in westernized but also traditional societies. Finally, we describe and assess influences of colour on human and animal agonistic behaviour.
Testosterone and human competition
Androgens are hormones involved in human male competition, antisocial norm breaking, dominant, and aggressive behaviour (Elias 1981; Susman et al. 1987; Mazur and Booth 1998). The androgen testosterone is a steroid hormone responsible for the development and maintenance of masculine features, but it is also found, in lesser amounts (in most species), in females. Studies of non-human primates have shown that a male’s status and testosterone levels are linked: elevated testosterone levels are recorded when males achieve high status, but decline again when status is lost (Eberhardt et al. 1980; McGuire et al. 1986; Setchell et al. 2008). Similar effects can be found in human competitions; sporting winners gain more status than losers (Mazur and Booth 1998) and males achieving high status are likely to have increased testosterone levels as a result (Mazur and Lamb 1980). Higher testosterone levels have been associated with offensive behaviour such as attacks, fights, and threats in male judo competitors (Salvador et al. 1999) and winning tennis players have also been reported to have increased testosterone levels (Mazur and Lamb 1980; Booth et al. 1989). Male basketball players were found to have higher testosterone levels the more (p.291) their individual contribution to the team outcome (González-Bono et al. 1999) suggesting that this is a highly consistent relationship.
Although the relationship between human aggression and testosterone levels is still debated (Archer 1991), Mazur and Booth (1998) concluded that competitiveness and dominance in humans appear to be linked to testosterone and that testosterone encourages ‘behavior apparently intended to dominate – to enhance one’s status over – other people’. Intriguingly, if a sportsman anticipates a competitive event as being a real challenge, his testosterone levels rise directly before competition; if he wins, his testosterone rises after competition relative to the loser (Mazur and Lamb 1980; Elias 1981). The function of such changes remains unclear, but Mazur and Booth (1998) suggested that high testosterone in winners may prepare them to engage in subsequent competitions and that the decrease among losers may prevent them from injury as they withdraw from further challenges. Mehta and Josephs (2006) showed that a male’s decision on whether to go back into a game, having lost a one-on-one competition against another man, can be predicted by the direction of change in his testosterone level. Although this was not a competitive sports setting, the same is likely to apply to physical competition. Indeed, Archer (2006) illustrated that sports competitions lead to larger increases in testosterone than contrived competitions.
Studies on hormones and competition in humans have mostly focused on male athletes. Limited evidence suggests that women are generally unresponsive to the effect of competition on testosterone (Mazur et al. 1997). However, Bateup et al. (2002) indicated that women’s testosterone levels are as responsive to competition as those of men. DeBoer (2004) argues that the motivation for competition differs with gender: women are motivated to express themselves and men are motivated to prove themselves. More evidence is required, but provisionally it appears that the relationship between testosterone and aggression is different in men and women (Archer 2006).
Other factors, such as a competitor’s mood (Booth et al. 1989), coping strategies, and state and trait psychological factors (Filaire et al. 2001), may also be important and should not be neglected in studies of endocrine responses of competitors. Similarly, behaviour influences hormones, as well as vice versa, so causal inferences cannot easily be made from correlations (Kivlighan et al. 2005). Studying hormones in humans is also challenging as ethical limitations make it difficult to manipulate hormones and measure aggressive behaviour. Overall, therefore, while it is clear that hormonal responses have an important role to play in sporting contests, the situation is complex, and psychological, biological, and anthropological elements must all be taken into account when assessing the role of endocrine responses in competition.
It is common knowledge that teams have a greater chance of winning whenever the match takes place at their home venue, and this general perception is supported by statistical analyses (Pollard and Gomez 2009). The received wisdom suggests that the home fans are tantamount to an extra player on the field, with the visitors having to cope with the home fans’ hostility and inimical shouting and chanting. The visiting team may also have made a long journey to reach the venue, possibly with a night in an unfamiliar hotel, while the hosts remain at home and follow their familiar routines. The combined effect is thought to give the home team the edge in the game, a well-documented phenomenon referred to as the ‘home advantage’ (Neave and Wolfson 2003; Pollard and Gomez 2009). Despite being a robust effect, home advantage varies season by season, from region to region, across divisions, and from sport to sport. Indeed, levels of home advantage appear highest in the early years of each league’s existence in all sports (Pollard and Pollard 2005b; (p.292) Pollard and Gomez 2009). Interestingly, declines in home advantage have been reported over the last two decades in ice-hockey and basketball, as well as a large drop from 67% to 60% in English football after World War II (Pollard and Pollard 2005b).
Crowd support, in both team (Schwartz and Barsky 1977; Nevill et al. 1996) and individual sports (Balmer et al. 2005), travel fatigue and geographical distance (Clarke and Norman 1995; Pollard 2006b), familiarity with the pitch (Pollard 2002), and referee bias (Nevill et al. 2002; Dawson et al. 2007) are clearly all fruitful explanations for the robust home advantage phenomenon. However, none of them has been proved to have a very strong effect alone. Indeed, in their review of home advantage in football, Pollard and Pollard (2005a) proposed a model demonstrating that the interacting effects of various psychological factors and tactics, rather than any single cause, led to home advantage. They noted that levels of home advantage were variable across European domestic football leagues, with Balkan nations showing a much higher home advantage (79%) than elsewhere. The authors suggested that the territoriality principle of Neave and Wolfson (2003) was likely to be a good reason for high home advantage numbers in regions like the Balkans, where considerable conflict is part of each country’s recent history.
Neave and Wolfson (2003) explored the relationship between testosterone, dominance, and territoriality in human competitive encounters. The authors define territoriality as ‘the protective response to an invasion of one’s perceived territory’, which is also prevalent in various animal species giving residents ‘home advantage’ in territorial disputes (Alcock 1998). Intruders trigger territorial aggression and a rise in circulating levels of testosterone in residents (Wingfield and Wada 1989). Intriguingly, similar effects are found in humans: a footballer’s salivary testosterone concentration is significantly higher before playing games at home than away, and this effect is further increased when the opponent was an ‘extreme’ rival (Figure 18.1) (Neave and Wolfson 2003). Strikers (specialist goal-scorers) generally had the highest levels; goalkeepers had the highest concentrations when playing against a bitter rival but the lowest levels in training sessions. Even though sample sizes were small and further investigation is required, Neave and Wolfson (2003) argued that goalkeepers, as the last defending line in a team, might be particularly inclined to testosterone changes when facing an important opponent. They concluded that their results suggest that testosterone, a hormone associated with aggression and territoriality in humans (Mazur and Booth 1998) and non-human animals (Nelson 2001), plays a mediating role in the
Knowledge of the potential hormonal basis of home advantage offers up a series of avenues for future research. Pollard (2006a) states that the direct analysis of hormone concentrations could deliver fruitful insights into the high levels of home advantage in players from Balkan countries. Neave and O’Connor (2009) highlight the need to determine ‘how individual differences in testosterone might relate to performance during a game, and whether it is possible to (legally) manipulate testosterone to improve team performance when playing away’. Additionally, it would be interesting to test for ‘leader effects’, since a team’s captain or coach may also show additional testosterone changes; indeed winning has been shown to lead to increased testosterone levels even in fans (Bernhardt et al. 1998). Conversely, it might be possible to discover ways of mitigating loser effects mediated by testosterone reductions. Cortisol levels (which measure stress responses: Sapolsky et al. 2000) could also be a promising avenue for further research on territoriality in both male and female athletes. Overall, examining the endocrine responses associated with home advantage has opened up an exciting range of opportunities for future research that could greatly enhance our understanding of the complex inter-relationships of factors explaining home advantage and success in sports.
While the precise hormonally-mediated mechanisms remain elusive, home advantage is nevertheless a robust phenomenon. Knowing that home advantage can have such a major influence on sports outcomes, it is crucial for sports teams, their coaches, and psychologists to prepare for, minimize, and even counteract these effects when walking into an unfamiliar stadium. Wolfson and Neave (2004) discuss potential strategies, emphasizing the importance of discipline, concentration, mental preparation, and the establishment of rituals. At the same time, future research may identify ‘legal’ ways of raising testosterone levels through behavioural means (Neave and O’Connor 2009). As a consequence, while home advantage remains a robust and widespread phenomenon, its effects seem far from insurmountable. Recent decades have seen a decline in the magnitude of home advantage across a range of sports (Pollard and Pollard 2005b) and future research has the potential to increase the speed of this downwards trajectory.
The list of famous left-handers extends to all walks of life, including leading scientists such as Albert Einstein, Marie Curie, and Isaac Newton; artists such as Michelangelo and Leonardo da Vinci; and politicians such as David Cameron, Winston Churchill, Barack Obama, Bill Clinton, and Benjamin Franklin (indeed five of the last seven US presidents are reported to be left-handed). It is amongst sportswomen and sportsmen, however, that left-handedness appears especially common, with a high representation amongst athletes considered amongst the greatest ever in their sport: Babe Ruth (baseball), Garfield Sobers (cricket), Pelé, Diego Maradona, and Johan Cruyff (soccer), Mark Spitz (swimming), and John McEnroe and Martina Navratilova (tennis) were all left-handed. To what extent is such anecdotal evidence supported by more systematic analysis?
Though frequencies of sinistrality (left-handedness) vary across human cultures and can range between 3.3% and 26.9% (Faurie et al. 2005), a consistent minority (10–13%) of individuals in all human populations is left-handed (Raymond et al. 1996; Raymond and Pontier 2004). Such frequencies have a long history, and have existed since at least the Upper Palaeolithic (Faurie and Raymond 2004); similar patterns are also reported for chimpanzees (Hopkins and (p.294) Morris 1993, McGrew and Marchant 1999). It has therefore been suggested that some sort of evolutionary mechanism must be involved in the persistence of this polymorphism (Llaurens et al. 2009b).
While left-handers are overrepresented in interactive forms of sports such as fencing (50%), table tennis (32%), badminton (23%), cricket (18.5%), and tennis (15%) (Bisiacchi et al. 1985; Aggleton and Wood 1990; Coren 1993; Goldstein and Young 1996; Raymond et al. 1996), sports without dual confrontations or direct opponents, such as swimming (Raymond et al. 1996), skiing, cycling, or gymnastics (Grouios et al. 2000) show no such bias (Figure 18.2). Furthermore, the smaller the physical distance between opponents (such as in combat sports like karate and judo), the higher the frequency of left-handed individuals (Grouios et al. 2000). For many sports, the advantages of left-handedness have been long recognized (Hagemann 2009; Harris 2010), and in some sports left-handed players are thought to hit with greater power (cricket: Brooks et al. 2004; baseball: Grondin et al. 1999). These effects are not confined to elite athletes; expert, intermediate and novice tennis players all find it more difficult to predict the direction of strokes by left-handers than those of non-left-handers (Hagemann 2009). Being left-handed, therefore, appears to be advantageous in interactive sports.
(p.295) The role of left-handedness and laterality in sports has attracted interest from researchers from sports psychology, neuropsychology, kinesiology, as well as evolutionary psychology, biology, and anthropology (Annett 1985; Porac and Coren 1981; Aggleton and Wood 1990; Faurie et al. 2005). In the context of sport, a simple reason why the minority of left-handers have an advantage has been termed the ‘surprise effect’ (Coren 1993; Faurie and Raymond 2005). Since the majority of sportspeople are right-handed, right-handers are more accustomed to competing against opponents favouring the same side. As a consequence, when they encounter a left-handed opponent, who already has the advantage of being practised to compete in a mostly right-handed world, right-handers find themselves at a disadvantage. Left-handers thus have a frequency-dependant advantage (Goldstein and Young 1996; Brooks et al. 2004).
Such effects are not restricted to ritualised Western sports, and left-handers are more frequent in most warlike and violent societies (Raymond et al. 1996; Faurie and Raymond 2005). Indeed, the ‘fighting hypothesis’ (Raymond et al. 1996; Faurie and Raymond 2005) suggests that left-handers thrive in traditional societies with high levels of violence because of the inherent advantages of left-handedness in these aggressive interactions. Across a range of societies, the frequency of left-handedness correlates positively with homicide rates (Figure 18.3). For instance, in the Dioula population of Burkina Faso, murder rates are as low as 0.013 murders per 1000 residents per year, and there are only 3.4% left-handers within the population. In contrast, 27% of the Eipo of Irian Jaya are left-handed and three out of 1000 inhabitants are murdered each year in this society. One possible interpretation is that, in confrontations where death and injuries are likely, left-handedness confers a competitive advantage. It is not, however, currently possible to exclude alternative hypotheses, such as a causal relationship between androgens and both handedness (e.g. Mathews et al. 2004; Sperling et al. 2010) and homicide rates (Dabbs et al. 2001).
Various environmental and developmental factors have been identified as playing a role in hand preference determinism (reviewed by Llaurens et al. 2009b), while genetics may also play a
In order to understand left-handedness, it is sensible to investigate why a predominance of right-handedness may have evolved in humans. Various evolutionary hypotheses have been put forward, such as the development of language in the left hemisphere (Annett 1985). It has been suggested that an ‘impairment’ of the right hemisphere (thus, a possible negative influence on skilled performances such as fast reactions, fine control with both hands, and visuospatial thinking) may in some cases result in the left hemisphere language specialization that can be found in nearly all right-handers (Annett 1985). Right-handedness is also suggested to have evolved in association with one-handed throwing ability and its associated cognitive, motor, and postural demands as a possible pre-adaptation for the emergence of left hemisphere specialization in language and motor skills (Calvin 1982; Hopkins et al. 2005). Another idea is that infant handling on the left side permitted a caregiver to move freely on the right side for other purposes (Hopkins and Morris 1993). However, Raymond et al. (1996) and Grouios et al. (2000) emphasize that none of these hypotheses has been advanced to explain the ongoing existence and persistence of left-handers.
Outside of sports and competition, left-handedness is often reported to correlate with advantages in cognitive tasks and socioeconomic status (see review in Faurie et al. 2008), creativity (Newland 1981; Coren 1995), or in the existence of a larger corpus callosum (Witelson 1985). Better spatial and visual skills due to relatively larger right hemispheric brain regions are another suggestion as to why left-handers might have an advantage (Geschwind and Galaburda 1985). Cherubin and Brinkman (2006) asked participants to spot matching letters across their left and right visual fields, finding that extreme left-handed subjects were up to 43 milliseconds faster. It seems that left-handers are more bicerebral and that the transfer time between hemispheres is faster in left-handed than in right-handed persons (Cherubin and Brinkman 2006).
If left-handers have a fitness advantage in a variety of situations, why are they not more common? What are the costs that maintain left-handedness at low frequencies within most populations? Left-handedness is associated with several fitness costs including a lower height in adulthood, lower weight, higher age at puberty, lower life expectancy, diverse immune and neurological disorders, and an elevated accident risk (Olivier 1978; Coren 1989; Coren and Halpern 1991; McManus and Bryden 1991; Aggleton et al. 1993; Gangestad and Yeo 1997), though some contradictory evidence exists especially for reduced longevity (e.g. Wood 1988). Smaller size and weight (Olivier 1978) have obvious potential fitness costs for left-handers, particularly in relation to a male’s reproductive value (Pawłowski et al. 2000; Mueller and Mazur 2001). Right-handers also have advantages for some life-history traits, such as number of offspring, which is lower in left-handers (Gangestad and Yeo 1994; Faurie et al. 2006). The fitness costs of left-handedness thus appear to limit its frequency in most societies, and provide strong support for adopting an evolutionary approach in addressing the role of laterality in sporting contexts.
Evolutionary accounts also help to explain the higher prevalence rates of left-handers found amongst men (Annett 1985). Following from the fighting hypothesis (Raymond et al. 1996; Faurie and Raymond 2005), the importance that survival in violent fights has on men’s reproductive value and social status (e.g. Chagnon 1988) may directly increase the winners’ own fecundity. The Yanomamö offer one such example as warfare involves kidnapping females (Gibbons 1993) and left-handers may gain an advantage as their surviving offspring would pass on their genes. Interestingly, however, a child is more likely to become left-handed when its mother is left-handed (Porac and Coren 1981; McManus 1991). One explanation for the maintenance (p.297) of left-handed women in human populations is that they may benefit indirectly from their left-handed sons (Billard et al. 2005). Indeed, both male and female student athletes have been found to have more sexual partners than their non-sportive counterparts, and this effect is further elevated in high performance athletes (Faurie et al. 2004). Given the disproportionate prevalence of left-handed athletes, their sexual success may help to maintain the handedness polymorphism in contemporary societies, although this idea remains to be tested.
Left-handers are more frequent in traditional societies with high levels of violence and warfare due to the inherent advantages of left-handedness in these aggressive interactions. Similar arguments provide compelling evidence for the advantage of left-handed athletes in interactive sports, with the frequency-dependent benefits of sinistrality leading to an elevated frequency of left-handers in many sports. Although quantifying the costs and benefits of laterality remains challenging, it is clear that an evolutionary perspective offers unique insights into the role of handedness in sporting competition. Nevertheless, the evolutionary perspective offers few solutions to right-handed athletes; as long as left-handers remain comparatively rare, they will retain their frequency-dependant advantage in competitive and sporting interactions.
Colour influences in sports
Having won 15 German Cups and 22 German Championships, F.C. Bayern Munich is by far the most successful German football club. Liverpool and Manchester United dominate the roll call of English domestic honours, while Ajax is the Netherlands’ most decorated team. These successful teams are also united by a second characteristic; all have red as the primary colour on their signature football strip. Although this could easily be construed as pure coincidence, recent evidence suggests that clothing colour may play an important role in deciding sporting contests.
Two decades ago, Frank and Gilovich (1988) analysed penalty records of the National Hockey League and the National Football League and showed a bias in the referee’s judgement of black sports attire. In both sports, teams playing in non-black uniforms were penalized significantly less often than opponents wearing black. The data also revealed that a team’s switch from non-black to black sportswear was followed by a rise in penalties; whereas the change of a team’s colour from, for example, blue-and-gold to red-and-green uniforms, did not have the same effect. Although the authors could not find any difference in the likelihood of winning or losing a game when playing in black versus non-black uniforms, the study did indicate that the colour of attire can influence sporting contests.
The first evidence that colour might influence the outcome of sporting events was provided by Hill and Barton (2005) based on an analysis of four combat sports (boxing, taekwondo, freestyle wrestling, and Greco-Roman wrestling) at the 2004 Olympic Games in Athens, Greece. During this competition, red or blue uniforms were randomly assigned to competitors, providing a natural experiment. If colour had no effect on outcomes, an equal number of red and blue winners would be anticipated. Instead, Hill and Barton (2005) found that wearing red was associated with a significantly increased probability of winning, with 55% of all bouts won by competitors in red (Figure 18.4a). Wearing red appeared to tip the balance between winning and losing in close contests: significant effects were found when competitors were closely matched (60% red winners), but not in more asymmetric encounters (Figure 18.4b). Interestingly, no such winning bias due to colour effects was found in judo contests when opponents were dressed in either blue or white (Dijkstra and Preenen 2008). This suggests that while factors such as skill and ability will inevitably have the greatest say in determining sporting outcomes, the subtle effects of red colouration may decide contests where competitors are evenly matched. (p.298)
(p.299) Recently, a series of studies have provided substantial support for the role of colour in determining sporting outcomes. A review of English football data found an association between teams wearing red shirts and long-term success (Attrill et al. 2008). Since World War II, red teams have provided more champions and averaged higher finishing league positions than teams in other colours. Most significantly, within cities with more than one team, red teams have significantly outperformed their non-red neighbours over the 55-year period (Attrill et al. 2008). Similar findings by Hill and Barton (2005) showed that teams at the Euro 2004 tournament had better results when playing in red. Greenlees et al. (2010) found that penalty-takers were least successful when they were opposed to a goalkeeper wearing red, supporting Greenlees et al.’s (2008) earlier finding that penalty-takers in red shirts are perceived to possess character traits such as confidence, assertiveness, and composure (compared with those in white). Such effects also appear to operate in virtual contests: Ilie et al. (2008) found similar patterns among experienced players in a first-person-shooter online computer game. Within the game, individuals joined either the red or blue team, and despite better players showing no preference for either colour, red teams triumphed in significantly more (55%) matches. A growing body of evidence thus suggests that the colour red may play a significant role in deciding sporting contests, although these relationships may be confined to male competitors (Barton and Hill 2005).
Why should wearing red enhance performance in human contests? One possibility relates to the biological and cultural associations between red and anger, aggression, and danger. On one hand, red’s signalling presence in traffic lights and stop signs reminds us to halt. On the other hand, red hearts and lingerie stand for romantic, passionate attraction and can even signal sexual opportunities, such as in red-light districts (Mahnke 1996; Kaya and Epps 2004). It is thus not surprising that women regard men as being sexually desirable and more attractive when presented in red clothing or on a red background (Elliot et al. 2010a, see also Roberts et al. 2010). Emotional states associated with red identify it as the colour of aggression, passion, anger, energy, and danger (Greenfield 2005). Encountering red in various ways causes ambiguous feelings in humans as positive and negative emotions are associated with the colour red. As humans, we have impressions such as red being intense and bloody, but also warm and passionate (Kaya and Epps 2004). Compared to that, black seems consistently negative, relating to death and evil in almost all cultures (Williams and McMurty 1970). Still, one would assume that different colours have various meanings in different societies and cultures. Surprisingly, despite cross-cultural differences in colour meanings, similarities in emotional states associated to colours were found. Adams and Osgood (1973) carried out a survey in 23 cultures and postulated an affective salience of the colour red. Mostly, red is perceived as active and black as passive. However, both colours are considered to be strong. This could explain why athletes’ performances are impaired as an opponent dressed in red may be perceived as particularly active. It could, however, also mean that just the simple fact of being dressed in red creates some sort of higher motivation/more activity in the wearer.
Darwin (1876) noticed that primate males use colouration for attracting females and displaying dominance. Subsequent studies of primates provide support for the significance of red. Recent evidence has found an adaptive link between primate trichromatic vision and their ability to distinguish mood differences due to redness in skin flushing (Changizi et al. 2006). The intensity of red colouration in rhesus macaques (Macaca mulatta) and mandrills (Mandrillus sphinx) offers a cue to male quality and status (Waitt et al. 2003; Setchell and Dixson 2001) and female rhesus macaques looked longer at images of redder males (Waitt et al. 2003). However, it is in male–male competition that the role of red is most pronounced. In mandrills, male red colouration on rump, face, and genitalia depends on their testosterone levels (Setchell and Dixson 2001) and Setchell and Wickings (2005) concluded that mandrills assess a rival’s fighting ability and dominance rank (p.300) based on the brightness of his red colouration. In fact, red colouration is associated with dominance and aggression in a wide range of taxa and may be a signal of intimidation to rivals (Tinbergen 1955; Pryke 2009).
In humans, skin redness is not such a pronounced signal. However, males tend to be redder than females (Edwards and Duntley 1939, in Ioan et al. 2007), and facial redness correlates with testosterone levels (Edwards et al. 1941), so may indicate high status and dominance. Redness due to oxygenated (redder) blood is a signal of increased aerobic fitness (Stephen et al. 2009a,b), whereas paler skin (reduced redness) can signal anaemia (Jeghers 1944) and can be caused by lower testosterone levels (Ferrucci et al. 2006). While blushing is a sign of social discomfort in situations of shame or embarrassment (Drummond and Quah 2001; Montoya et al. 2005), red skin colouration is also associated with anger and dominance (Drummond and Quah 2001) and blanching is associated with submissiveness, fright, and fear (Montoya et al. 2005; Changizi et al. 2006). Indeed, humans interpret skin blood colouration as an honest cue to underlying health (Stephen 2009a, in both Caucasians and black South Africans) and a ‘ruddy’ face is often associated with healthiness. Hence, there is evidence from humans and non-human species that red colouration signals both biological traits (health, testosterone, dominance) and emotional states (anger, arousal). It is also known that, in animals, artificial colours can exploit innate responses to natural stimuli. Cuthill et al. (1997) found that, when red and green leg bands were placed on the legs of male zebra finches (a species in which beak redness signals condition), red-banded males dominated green-banded males. Possibly, then, the effects of clothing colour in sporting contests in humans reflects a similar response based on the biological significance of natural skin redness.
What are the underlying mechanisms of these effects? Barton and Hill (2005) suggested the impact of colour might operate through hormonal influences such that wearing red may elevate testosterone levels in the wearer and/or reduce them in the opponent. So far only a small pilot study has examined this possibility and, while the sample size was too small for rigorous statistical analysis, there was qualitative support for athletes in red experiencing elevated testosterone levels (Hackney 2006—but note that Hackney interpreted the non-significant result as contradicting the hypothesis rather than due to lower statistical power). Further research is clearly required to assess the psychological and hormonal effects of wearing red, although a growing body of evidence is showing pronounced effects on the receivers of the stimulus.
Negative effects of perceiving (as opposed to wearing) red are now well documented. In an ingenious experiment, Hagemann et al. (2008) noted a perceptual bias in decisions taken by professional taekwondo referees in response to competitor colour. Hagemann et al. (2008) digitally manipulated video footage to reverse the competitor colours and found that the referees evaluated the identical performances of the taekwondo competitors differentially according to whether they were wearing blue or red protective gear. In the original video footage, the red competitors scored more points, but with the colours reversed, the original blue competitor, now shown in red, was scored more highly. The results provide compelling support for the association between red and dominance influencing perceptions of sporting success.
Sportsmen could thus be distracted by a ‘threatening stimulus’ such as the colour red, even if they are not aware of this fact (Elliot and Niesta 2008). Ioan et al. (2007) found that ‘seeing red’ was a particular distractor for men in competitive situations; specifically, men seemed to experience more interferences than women when they were asked to name the colour red in the Stroop test (e.g. reading the word ‘blue’ written in red). These findings support Hill and Barton’s (2005) view that red colour may act as a distractor for men through a psychological effect that evolved in response to sexual competition. Similar results were reported by Little and Hill (2007), who showed that in a study of perceptions of abstract shapes, red dominated the colour blue but the (p.301) social perception of these colours again differed with gender. Mehta and Zhu (2009) also reported a significant difference in avoidance motivation of red compared with blue conditions in cognitive tasks but, at the same time, red enhanced performance in detail-oriented tasks. Elliot et al. (2007) and others (Kwallek et al. 1997; Stone and English 1998) showed that longer wavelengths in colours such as red and orange degraded task performance and appeared to arouse, while short presentations of red have been found to significantly reduce motivation (Elliot et al. 2010b). This reduced motivation can even go so far that participants would knock fewer times on a door when briefly shown a red cover sheet for a test relative to participants shown a green one (Elliot et al. 2010b).
Colour thus appears to play a small but significant role in deciding sporting contests, with an increasing number of studies reporting the red advantage across a range of datasets. The results appear to reflect the evolutionary and cultural associations of red with dominance and aggression, and raise a number of significant implications. In particular, one repercussion of these findings is that colour represents a significant obstacle to ensuring a level playing field in sport, and suggests that governing bodies should play close attention to the colour of sporting attire. Recent analyses (Dijkstra and Preenen 2008) have shown that in judo, where competitors are assigned either blue or white outfits for each bout, there are no systematic colour biases in sporting outcomes. These results provide an easy solution to the influence of colour in many combat sports, where a simple change of colours could reinstate the level playing field. The situation is more challenging in team sports, however, since signature shirt colours often have a long history as well as enormous commercial value. Nevertheless, provided sporting associations are aware of the potential significance of colour in determining sporting success, individual teams can make their own informed assessments of the relative importance of sporting and commercial success. While this may inevitably bias results to those teams already using red as their signature colour, the opportunity at least exists for other teams to exploit this advantage.
Evolutionary approaches have significantly increased our understanding of the factors influencing the outcome of human sporting competitions. Across a range of sports, an evolutionary approach helps to explain phenomena such as home advantage, the high frequency of left-handedness, and the ‘red advantage’ in human competitive interactions. The evolutionary approach has also opened up new questions and areas of research, which, alongside traditional studies of sporting behaviour, may offer novel avenues for improving sporting performance.
The significance of testosterone levels has been a recurrent theme throughout the chapter, as endocrine responses appear to play a mediating role in territoriality, aggressive, and dominance behaviour. Clearly, humans and animals differ in the way they express aggressive or dominant behaviour, and yet the relationships between rank, aggression, and testosterone levels appear remarkably consistent. Further research is still clearly required, not least into gender differences in endocrine responses, but endocrine responses appear to underlie widespread phenomena such as home advantage, as well as recent investigations into the more subtle effects of colour stimuli. Given the significance of these effects for determining sporting outcomes, such evolutionary explanations increase the potential for further sporting enhancements, not least through investigations into how testosterone levels might be ‘legally’ manipulated before sporting encounters. Such investigations could adapt existing approaches or build on recent developments in evolutionary approaches to colour psychology, but either way the next few years offer exciting opportunities for research into factors underpinning sporting success in humans.
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