Evil Looking

I was thinking about spiders today and how they just look evil. I thought of it because I saw a caterpillar crawling on the window sill and just left it alone, while hours earlier I had killed several spiders that weren't doing anything to me. I thought about why I spared the caterpillar and not the spiders. I really think in some way it comes down to looks.

It's funny how shapes of things can decide if they look evil or not. I was reminded of something I saw a while back about the making of Disney's Aladdin where they were talking about how they came up with how the characters looked. They were noting how the bad guy has lots of points and harsh lines, while the good guys have softer, curved features. A while after I was thinking of this I was watching an old movie from 1963 called The Courtship of Eddie's Father. There was a scene where the kid, Eddie, was telling his dad that he likes a woman his dad is seeing and why he likes her. He said one of the reasons he likes her is because she doesn't have thin eyes, she has rounder ones, and she has a medium-sized bust, not a big one. The reason he said he knew based on these features that she must be a good person is because all of the villains in comic books have thin eyes and a big bust. It was odd I ended up seeing that since I was thinking about it earlier - denoted evil through appearance.

I wonder how this sort of thing came about. Do we inherently associate sharp harsh features and shapes with things that are bad? Do we think this way because nature actually works that way or have we been trained by culture to think this way? If every single movie and comic book uses the same signals to denote evil, is it because the ones before them did it and that's what people will understand, or is it something built into us? Does a shark look evil because we know it's dangerous, or does it actually look dangerous? Which came first, the chicken or the egg?