Let's say you were trying to design the optimal form of torture without regard for conscience, morality, humanity, law, and international obligation. Here are the features you would look for:
- Maximize physical discomfort: fire the most pain neurons possible, inhibit the pain adjustment reflex.
- Maximize psychological discomfort: incorporate instinctive fears and involuntary reflexes for synergistic effect.
- Minimize lasting physical damage: if possible "do not damage to the information container" before or after the information is communicated.
- Minimize physical evidence of trauma: Physical scars can prove that torture was used, and might reduce admissibility or credibility of the prisoner's confessions.
- Maximize your future torture options: You can't use stress positions if the participant's hands have been amputated. You can't show your prisoner his wife being raped if you've burned his eyes out.
- Minimize recovery time: the sooner you can get them coherent, the more likely that they'll answer questions. No wasting valuable interrogation time while your subject revives.