The Evolution of Right and Wrong

It seems that people observe and sometimes follow different "rule books" - written or unwritten - for morality. Let's assume for a moment that moral rules are inspired by these three major themes:

1. Individual liberty and freedom
   
2. Group sustainability
   
3. Benevolent sentiment and feeling

For example:

1.) Do what is "right" for your own existence
2.) Do what is "right" to maintain a group's survival
3.) Do unto others what yields a feeling of good

In applying the golden rule, each of the above has its corollary: Don't do what is "wrong" for...

These themes couldn't have been developed, however, if people couldn't apply an underlying sense of right vs. wrong. So how does our situational judgment of right and wrong function? Perhaps our moral apparatus is guided by base-level feelings of guilt, satisfaction, empathy and pain:

• If we feel guilty about something, it might be wrong.
• If we feel satisfied with something, it might be right.
• If we feel pain, and if we have empathy for others, we'll take actions so that they can avoid the same pain.

Questions:

• How is it that we're endowed with the mental ability to feel guilt, satisfaction, and pain? Where do these capacities come from? How and why were they selected?
• Why do some people act in a manner that suggests a preference toward one moral theme vs. another? What accounts for the magnitude of preference?
• What role does fear of hell/want of heaven play in motivating people to follow their inclinations of right instead of wrong and when did this motivation develop and become powerful?