Hey Lana, Your question brings up two different areas of thought for me:  1. Human curiousity as it relates to knowledge and learning, and 2. Human interest in death or the morbid.

I think that overall human curiousity is an evolutionary advantage - the ability of our brains to seek and retain information and then modify our behavior has allowed us to be more successful at living and reproducing as a species.

Specifically, the rubbernecking example (not sure if rubbernecking is an international term, so if you're looking for a definition, here's one: http://en.wikipedia.org/wiki/Rubbernecking) that you give may have more to do with our interest in death and dying.  Although I can't stand gory horror films myself (you can find me only peeking through my fingers), there are TONS of horror flicks out there, proving that people will pay to watch blood, guts and gore.

Death is an inevitable consequence of life, and yet there is so much that we don't know about it that fascinates the mind.  New Scientist has a whole entire topic guide of content devoted to the subject here:  http://www.newscientist.com/topic/death

We also had a special issue tackling big questions, among them, what happens when you die. http://www.newscientist.com/article/mg19225780.075-the-big-questions-what-happens-after-you-die.html

I hypothesise four attitudes with survival advantages:

(1) Figure out how the bad thing happened, so I can avoid it happening to me: e.g. stay away from tiger tracks.

(2) Figure out how I would cope with the bad thing, so if it happens again I have a strategy to deal with it: e.g. carry a bigger stick.

(3) Figure out if I can help, so that somebody might later follow my example and help me: e.g. chase off the jackals.

(4) Figure out if I can benefit from the situation: e.g. steal the antelope.

And maybe just checking the bad thing did not happen to somebody from your tribe, and being glad it wasn't you.