As for a specific group of people resistant to peer pressure—psychopaths. Psychopaths don’t conform to peer pressure easily—or any kind of pressure, for that matter. Many of them are in fact willing to murder, sit in jail, or otherwise become very ostracized if it aligns with whatever goals they have in mind. I’d wager that the fact that a large percentage of psychopaths literally end up jailed speaks for itself—they just don’t mind the consequences that much.
This is easily explained due to psychopaths being fearless and mostly lacking empathy. As far as I recall, some physiological correlates exist—psychopaths have a low cortisol response to stressors compared to normies. On top of the apparent fact that they are indifferent towards others’ feelings, some brain imaging data supports this as well.
What they might be more vulnerable to is that peer pressure sometimes goes hand in hand with power and success. Psychopaths like power and success, and they might therefore play along with rules to get more of what they want. That might look like caving in to peer pressure, but judging by how the pathology is contemporarily understood, I’d still say it’s not the pressure itself, but the benefits aligned with succumbing to it.
For fun, I tried this out with Deepseek today. First went a single round (Deepseek defected, as did I). Then I prompted it with a 10-round game, which we completed one by one—I had my choices prepared before each round, and asked Deepseek to tell its choice first so as not to influence it otherwise.
I cooperated during the first and fifth rounds, and Deepseek defected each time. When I asked it to elaborate its strategy, Deepseek replied that it was not aware whether it could trust me, so it thought the safest course of action was to defect each time. It also immediately thanked me and said that it would correct its strategy to be more cooperative in the future, although I didn’t ask it to.
Naturally I didn’t elaborate the weights properly (using the words “small loss”, “moderate loss”, “substantial loss” and “no loss”) and this went only for ten rounds. But it was fun.