system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What's the psychological mechanism behind why incestual porn is so popular but most people are grossed out by the thought of having sexual relations with a family member in real life?
gpt
Kind of guessing here but one answer that comes to mind is how arousal works. There are studies that show that being sexually aroused or anxious are not really that different, mostly the context is different. So the wires cross fire when it comes to incest. Incest is "wrong", which makes you anxious and uncomfortable, coupled with sexual arousal it intensifies it, which is where the "forbidden fruit" arousal comes from, basically because of us feeling it's wrong.

However, it's still a fantasy, you can enjoy fantasies but in real life you would never want to do it. It's almost like you're highjacking the anxiety that the idea incest gives you for a better sexual high, but wouldn't want to do it in real life. Same way with how we kill people in video games because we high jack the high, but would never want to kill someone in IRL.

Also from what I've seen the most popular porn seems to be "step moms" and cousins, and cousins don't count!