Does home field advantage matter? In baseball outfielders, the tricks and corners of a new baseball park might be meaningful but that effect should diminish over time. The Seattle Seahawks have a famously loud stadium and the team calls the audience "the twelfth man" but they didn't need it to rout the Denver Broncos in the Super Bowl.

There are no athletes in the Olympics who are from Sochi, yet psychologists believe that Russian athletes will have a psychological edge, even though Russia covers 6,600,000 million square miles, because they have a home field advantage.

Psychologists Mark S. Allen of London South Bank University and Marc V. Jones of Staffordshire University conducted a literature review and find that there is support in journal articles for the idea of a "home field advantage" - among psychologists, anyway.

Two different models have been proposed to explain any advantage of playing on home turf: the standard model and the territoriality model. The standard model includes several factors that can influence the psychological states of competitors, coaches, and officials, ultimately impacting their behavior in ways that tend to favor home athletes. For example, larger home crowds might show encouraging behavior, like cheering, that become linked with home team success. Crowd noise may even impact the kinds of decisions that officials make: When the home crowd is noisy, they psychologists write, officials are more likely to make discretionary decisions (such as awarding extra time) that favor the home team and dole out harsher punishments (such as warnings) for the away team, which is sure to alarm the NFL, or Major League Baseball, which uses no clock. The NBA, sure, bet on the home team, but not for reasons that have anything to do with a home field advantage.

But the crowd can't be much of a factor, since this perceived advantage remains even when there is no audience. The authors speculate it might be due to travel fatigue suffered by the away team and they cite one paper which claims that the home advantage increases by as much as 20% with every time zone the away team must cross, which clearly was written by someone who had never played a day of sports in their life.

The territoriality model, on the other hand, specifically frames the home advantage as a reflection of players' natural tendency to defend their home turf. One study said that soccer players showed significantly higher testosterone levels before home games than before away games and neutral training sessions. And additional research suggests that increased testosterone may benefit athletic performance through physical aggression and motivation to compete, though the relationship between testosterone and performance needs to be further investigated in the context of competitive sport.

Playing at home can have disadvantages as well, they say.

Cortisol, a stress hormone, is higher when performing at home, adding to self-reported survey data finding that athletes feel increased pressure to succeed in front of their own fans. Studies show that in high-pressure, high-importance situations, athletes may shift their attention in an effort to control typically automatic movements. They overthink what they are doing and this conscious control often leads to worse performance, what spectators call "choking" under pressure.

Each of the home-field advantage models claims evidence to support their premises, but it's still unclear how, or whether, they fit together.  Or if it could matter at all, beyond nationalistic pride. A basketball player from Florida does not feel home field advantage in California, for example, until it's the Olympics and then somehow he does.

So, will the Russians feed off the energy of their home crowd and rack up the medals, even though athletes from Georgia may live closer to Sochi? Or will Russians suffer from the pressure of having to live up to the expectations of their countrymen? We'll be no closer to knowing in two weeks but both sides will claim support for their hypothesis.