Here's one study if you want to take a look at it.

https://sci-hub.st/10.1111/j.1469-8986.2005.00279.x

Bruno Verschuere is the researcher who did the comparison between U.S. and Netherlands prisoners. I can only find a reference to that study in an article though, and haven't been able to find it published online. He seems to do a lot of research in this area (he's one of the researchers in the linked article).

Anyway the link should give you an idea on controls they're using. The linked study is actually about lie detector tests and if they're less accurate on antisocial people as they have less autonomic reaponse when lieing.

They are hard to spot though. I did some time in prison for growing psilocybin. I wanted to believe my celley was a good person because he was easy to get along with and seemed kind. Looked him up when I got out, fucker had a taste for little girls and I had pictures of my young son up in our cell the whole time...

But you can sorta learn to spot it. If you watch the documentary on the Nexium cult or other cult leaders you might see what I mean. They don't seem to have the same fear response about hurting others and it's visible in the eye movements.

That's my hot take at least. And I've been enjoying this conversation btw.