Imagine the Roman Colosseum in AD80. Completed by Titus but commissioned several years earlier by his old man, Emperor Vespasian, in an attempt to gain popularity by staging fights between wild beasts, men or both, it hosted slaughter on a grand scale: at its grand opening that year, more than 9000 animals were killed.
Described by one cultural commentator as a ritualised hunt satisfying an increasingly urbanised population, those Roman Games might be separated from the current Rugby World Cup by almost two millennia of history, of social change, yet a consistent buzz remains: the thrill of competition.
In New Zealand last Sunday, a television audience of almost two million tuned in to watch the All Blacks' 20-6 semifinal win over Australia; across the Tasman, the audience figure was 3.23 million.
Elsewhere, French channel TF1 drew an audience of 9.5 million for the semifinal against Wales, a match that also attracted much attention in the United Kingdom where 6.6 million people watched the last 15 minutes of France's 9-8 win over Wales.
In another chapter on the continuum of sporting evolution, we (and, of course, the French) hold our breath as the clock ticks towards tomorrow night's final at Eden Park.
Blood might spill (as it did from the faces of All Blacks Cory Jane and Andy Ellis and Australian midfield back Pat McCabe last weekend); tears might roll (as they did down the faces of various New Zealand players after shock losses to the same team in 1999 and 2007); some political commentators have even suggested the result could affect the forthcoming election.
Yet, why should sport compel us to such a degree?
It seems the forces at play are both internal and external.
The Gale Encyclopedia of Psychology (2001), describes competition as "an inevitable consequence of the psychoanalytic view of human drives and is a natural state of being".
Sigmund Freud, the founder of the field of psychoanalysis, believed humans are born screaming for attention and brimful of drives for fulfilment in various areas. According to his view, we initially compete for the attention of our parents; as we age, we juggle between base impulses for self-fulfilment and social and cultural rules which steer us away from pure indulgence.
In his 2003 book, Human Instinct: how our primeval impulses shape our modern lives, Robert Winston offers a personal example of his passion in supporting the England soccer team.
Saliva samples taken every 10 minutes during England's 2002 World Cup soccer match against Argentina reveal Winston's testosterone levels doubled immediately after David Beckham scored from a 44th-minute penalty and rose again when the final whistle confirmed the 1-0 victory.
In such self-examination, Winston cannot ignore Charles Darwin who, with The Origin of Species, established the doctrine of natural selection (those species best able to adapt to and master the natural environment in which they live will survive).
"Competition between members of the same species is the engine that drives natural selection," Winston writes. "Think back to the explosion in brain development which separated the Homo lineage from that of the great apes. Each step along the way ... was a product of humans competing for mating opportunities, and for resources such as food, water and shelter."
According to Winston, we see the imprint of this constant conflict, rivalry and competitive game-playing in ourselves today.
"Over aeons of evolutionary time, it has indeed left its mark on our psychological makeup ... the instinct for competition plays a role in every branch of human endeavour, from the writing of symphonies to new scientific discoveries."
However, there is a strong cultural component to our competitive inclinations, too.
Winston, widely known for his scientific publications and television documentaries on human-related topics, also states any genetic components that might drive our behaviour are, crucially, refracted through the lens of social norms and expectations.
"We are forced as a species to walk through life weighed down by the genetic baggage of five million years of savannah psychology, but here we live in an age where we are bombarded by social constructs."
Auckland-based sociologist Nick Perry agrees.
Author of the recently released Ruling Passions, a series of academic essays covering everything from the media's dissemination of rugby to globalisation, Perry says our pursuit of play includes no small measure of self-identity. By pulling on that replica shirt, we are pulling on a comfortable mask of sorts.
Earlier this week, Aaron Cruden, called into the All Blacks because of injuries to Dan Carter and then Colin Slade, talked of his childhood fantasies, of scoring a winning try or kicking a crucial penalty. Some might call it a boyhood dream; more formally, Perry describes it as a "culturally proscribed notion" of appropriate social identity.
"One of the ways in which small children learn about co-operation and competition is through sport.
"That is something not peculiar to New Zealand. Sport is something you can become deeply implicated in but it is wider than oneself. The fact this process takes place across cultures, across the planet, suggests there is something profoundly significant about it," Perry explains.
"When small children first start playing sport, they think only of themselves chasing a ball across a field. It is only gradually they learn that in order to play the game better, they might need to run away from the ball rather than towards it. What that means is they are beginning to get an idea of the significance of not only themselves but of the wider social order.
"Sport, of course, is about competition. But it is the way it mediates between notions of co-operation on the one hand and competition on the other that is quite striking."
Psychologists refer to five general motives for ambitious (or competitive) behaviour:There are physiological drives such as hunger, thirst and sex; there is also an aggressive component; and there is a need for achievement.
Dr Kristin Hillman, of the University of Otago's psychology department, says in regards sport it is the latter two that hold most sway.
"The goal of any competitive situation in a naturalistic, evolutionary, biological perspective is self-preservation.
"You want to keep yourself alive long enough to find a mate, to reproduce, to find food and water, things like that. There is a drive to compete for those things to ensure your own survival. Aggressive or competitive behaviour is part of that."
Dr Hillman is interested in the neural basis of ambition/drive (she recently received Marsden funding to support research into this area).
"I look at cost-benefit analysis, how the brain makes decisions as to whether you should incur a cost to get some sort of benefit out of it. The field is called neuro-economics; it's putting your brain into an economic [note: not in a fiscal sense] decision-making paradigm."
She says most animals, including humans, avoid effort if possible ("We don't like to be put into a situation of extra work if we don't have to"). However, effort will be made if the goal is deemed worthy enough.
But what makes some people - or even rats - more competitive than others?
Let's go to the front of the brain ...
"From a neuroscience perspective, the question of what makes some people more competitive than others, our research suggests it may in part be due to differences in brain signals in a region called the anterior cingulate cortex (ACC, a region of prefrontal cortex).
"Last year, we ran some experiments in laboratory rats where we recorded brain signals in the ACC as the rats made decisions as to whether to compete against another rat for food reward. The rats that did choose to compete - and compete effectively - had stronger neural-level activity in the ACC," Dr Hillman says.
"These rats were smart decision-makers; they knew when it was 'worth it' to compete and persist and when it was not worth it, so the ACC seems to enable a level of cost-benefit analysis when it comes to effortful competition. Strong ACC signals tell you to 'do it, compete' because it's going to be worthwhile.
"What's exciting is that regular training in competitive/effortful situations seems to strengthen this ACC signal, and this is what we plan to investigate further."
To extend the hypothesis to sport, regular, effortful pursuits (e.g. a hard training session or a tough match) may strengthen the ACC signal, optimising competitive effort when required (for instance, in a Rugby World Cup final).
"My training is in neuroscience, not psychology, so I am answering the question from a more mechanistic, neural angle," Dr Hillman explains.
"From a neuro-reductionist perspective, all behaviour stems from the brain, so what makes some people exhibit more competitive behaviour than others has got to be signalling differences in the brain. We're trying to pinpoint exactly what those differences are. Work so far suggests ACC signals are likely key."
Dr Hillman says, so far, much of the neural research in regard to competition has focused on aggressive behaviour and reward.
"Aggression studies usually focus on the limbic system of the brain - an older portion of the brain associated with instinctual drive and emotional reaction. Strong signals in this region would drive a person to be aggressive or competitive. However, overactivation in this region typically correlates to overly competitive, aggressive or confrontational behaviour, usually to a pathological level.
"Reward studies usually focus on the dopaminergic system of the brain.
"When we desire something and receive it (i.e., a reward) a lot of dopamine is released from the midbrain. So if we desire something strong enough, dopamine can help drive us to compete for it."
This can have a snowball effect, Dr Hillman says.
"When we obtain the reward, further dopamine is released, which reinforces the behaviour, so we compete again."
Ken Hodge, associate professor in sport and exercise psychology at the University of Otago's School of Physical Education, says there is no shortage of research into what motivates people to compete.
"The focus has been far more on why people play and what objectives they are trying to accomplish than on competition, because it is easier to conceptualise, to measure and make sense of.
"For example, there are some people who argue you can't compete against yourself. The average punter would say 'sure I can; I just go for a run and try to beat my personal best'. But a psychologist would say that is not the same beast as competing against another person; your ego is not threatened as much. That's where it becomes a bit slippery.
"The idea of why do people play anything in a recreational sense is as the word suggests: we are trying to re-create ourselves."
In other words, dreams are free. They can also come true.
