Most of us spend a lot of time indoors - and that ceiling somewhere above our heads has a lot of influence on us psychologically.

We're more creative in spaces with higher ceilings. All else being equal, people are more innovative in places with 10 foot ceilings than they are when the ceiling hovers 8 feet above the floor.

When the ceiling in a room we're in is lower than about 9 feet, we start to feel crowded and want other people (except those we're on really good terms with) to stay farther away from us. If we feel crowded or cramped we get stressed and distracted from whatever we're trying to accomplish.

Really high ceilings produce negative effects, as well. The great rooms in McMansions never feel cozy because their ceilings are so high that they distort the socializing happening under them.

Not only do we look at other people to determine how far away from us they are, we also consider what they sound like when we're locating them. When sound from another person is bouncing off of a higher ceiling, we feel farther from that other person - as if we're standing at the appropriate distance for the formal situations that normally take place in rooms with high ceilings. To make everything square up in our minds, when the sensory cues we're getting say "formal situation," we act formally. When we're in a space with ceilings around 9 feet high, we're more likely having a conversation with a friend and interpret the sound bounce we encounter in that sort of setting accordingly. When ceilings are really low, say 5 feet, we expect to be with people that we're intimate with. Interestingly, the top of a canopy bed is normally about 5 feet above sleepers' heads.