With psychopaths and sociopaths, it's very hard to experiment with full accuracy. Psychopathic tendencies derive from a lack of emotions or empathy. Tring to spot a psychopath is quite easy; psychopath test and psychopath quiz are all based on seeing whether you lack emotions or not. Creepy psychopaths exist but absolutely normal psychopaths exist as well. How to tell if you're a psychopath or not is quite simple: Usually, if you're questioning it, you're probably not a psychopath.

source: DanPlan