From reading about this, I think there is a very big environmental component to Norris’s pathology. His mom was a drug addict and there was allot of neglect and abuse. He wasn’t loved or shown love and was constantly in and out of foster care, where he was raped. I think his upbringing caused him to detach emotionally and warped his sexuality.

Bittaker’s childhood, on the other hand, wasn’t as terrible. You look in his background though, and you see criminal behavior, impulsivity, manipulation, lack of remorse, lack of empathy, unwillingness to accept responsibility, etc. He obviously was a severe psychopath. He wasn’t wired normally and was likely born with predispositions for antisocial behavior.

When Bittaker met a guy like Norris who’d already crossed the threshold into sexual violence, he didn’t care. People who aren’t psychopathic would respond with revulsion. Bittaker didn’t see anything wrong with what Norris did, it was just something he himself hadn’t tried. Bittaker quickly eclipsed Norris in his sadism during their spree, because he naturally lacked inhibition.