Don't most people observe moral or 'good' behavior out of fear? We are social creatures, and on some level want to belong to the group, so we adapt our behavior as much as needed in order to belong. We fear the rejection of the group, both the immediate group (family, friends, co-workers, etc) and the larger group (community, society, etc). Some people add an additional layer --or group-- via religious morals, but I don't think they abandon the other groups.
"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape- like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered."
-Stephen Jay Gould
-Stephen Jay Gould
