Owen S Mouth, thanks for the reply. I freely admit I have an interest in this subject, that is why I posted. Yes, my own personal psyche is involved, but I am also wondering about the personal psyche of the solo male actors and the producers. Why put scenes like this in straight porn?
I do wonder why men would agree to masturbate in front of the camera without joining in on the action. As I said, I don't think it is money. And regarding the difference between just jacking off and joining in on the action, I think most men wouldn't mind if their friends saw them boning a beautiful woman in a porn. What man doesn't want to be in a porn with a drop dead gorgeous woman? However, what guy wants to be the lone stroker whle watching a hot couple go at it? Most guys would be totally embarassed if their friends saw them just masturbating in a porn movie. Masturbating is generally something you don't brag about to your friends, fucking beautiful women is.
So I guess we're back to my original question. Why do you think men jack off in porn knowing that thousands of other men will see him naked and stroking off, possibly even friends, acquaintances, and family?