[textor]

You're going too far generalizing from your experience. They can imagine just fine, as their cognition is unimpaired. But humans are learning and planning largely on emotional basis. Their amygdala is less functional, so their imagination is decoupled from negative emotion: when they imagine some bad outcome, they process it in the detached way most people process heat death of the Universe or hunger in Africa, i.e. something that is maybe significant but has little bearing on actual choices. It doesn't generate aversion. What does generate it, though, is deprivation of positive stimulus, so when "bad outcome" means "being put in a small concrete cage with no entertainment and bland food", they'll strategize rationally and do their best to avoid being caught. When it means merely being shunned, reviled, disowned, demoted, physically hurt, it doesn't affect the strategy very much. They don't want being hurt in the present moment, theoretically, but they can't feel enough to factor this into their planning.

It's kind of like how overeating people struggle to curb their craving now with thoughts of seeing their weight increase later. Some succeed, and some can't do it at all. They'll feel negative emotions when they look at the scales, not when they get the ice cream and imagine the numbers. Except psychopaths don't even want to fight this tendency of theirs.

To be fair, positive reinforcement works for them about as well as for others.