Man City will test that theory to the full this year. Colour has no bearing at all that finance and budget can't overcome. They're basing it on the fact that historically in this country our best teams just happen to be predominantly red.
Remember some scientific research a few years back saying that teams in stripes can sometimes have an advantage over opponents as the shirts always make the player wearing them appear bigger.
Does anybody remember that keepers kit Chelsea released that was meant to be the most distracing colour to put the forwards off, they conceded more goals that season then any in the previous 5 or so. It's all the mind with things like that and they have no real bearing in the real world.
Shankly wanted his players to be more distinctly dressed, so he decided to update the kit, changing the white shorts and socks to red. Liverpool played in all red for the first time against Anderlecht, as Ian St. John recalled in his autobiography:
He thought the colour scheme would carry psychological impact—red for danger, red for power. He came into the dressing room one day and threw a pair of red shorts to Ronnie Yeats. “Get into those shorts and let’s see how you look,” he said. “Christ, Ronnie, you look awesome, terrifying. You look 7ft tall.” “Why not go the whole hog, boss?” I suggested. “Why not wear red socks? Let’s go out all in red.” Shankly approved and an iconic kit was born.[33]