Today's scientific models are not the most useful way to explore and measure things like morality. That said, through observation, you can for hypotheses like:

- Morality is wired emotionally (that is, if I tell you to rape your grandma, your reaction won't be one of "well logically, that's not moral" but rather, completely kinesthetic (that just feels... ugh)... you'd be _repulsed_ by the thought.

- simplistically, emotions are fired off by chemicals produced by the various "free drug factories" that exist within your body.

- What controls when those chemicals fire off and how, is how you're wired, which can come from both initial conditions, and how you developed (how you were raised, nurtured, what you were exposed to, etc.)

So it all comes from the wiring you've built up over time. Think about all the morality debates you read about, be it the death penalty, or gay marriage, and realize that ALL opinions are basically feelings. The anti-gay-marriage argument is based entirely on "ewww gross" and all the rhetoric around it is just justification to cushion and justify your raw feelings about it (where ever those feelings may have come from). And when we try to use logic to justify those feelings, that's when the popcorn-eating really begins.

But again, that "wiring-level" stuff is just not the most useful way to have a conversation about whether it's okay to murder criminals, etc.