Right-handers unconsciously associate good with the right side of a space and bad with the left side.
Full article here and remember: In English, ‘right’ is also the opposite of wrong. Anyway, the most interesting part of the story:
In their experiments, when people were asked […] which of two alien creatures looks more intelligent, right-handers tended to choose the […] creature they saw on their right, but most left-handers chose the one on their left.
Isn’t the human brain amazing: It analyses which alien looks more intelligent, and comes to the conclusion that it must be more dangerous. Luckily our brain then remembers that we have the weapon in that hand that gives us nice, straight shooting line to kill the beast.
Alles wird gut.