Often you hear about the team whose ground the match is being played at having a "home advantage".

During a discussion with a friend they said teams go as far as to style the opposing teams changing room to play mind games; i.e. making the room layout hard for discussion, and the colour scheme being dull so as to lower any motivation.

Personally I thought this was a bit too far (sportsmanship anyone?), but I was curious as to what actually contributes to a home advantage?

Additionally, does anyone know of any studies/ statistics which can prove whether the home advantage is merely a myth, or is a real thing?