The clearest example of negative reinforcement in this novel is of course the way that Alex is "cured" of his violent tendencies through associating extreme violence with illness. The Ludovico Technique works through associating illness with acts of violence in order to create those feelings of extreme sickness whenever the person tries to commit a violent crime or is tempted to strike out. This is the biggest example of negative reinforcement in this novel, as Alex is unable to act in the way that he wants to. However, this also raises the novel's central ethical issue, as the Ludovico Technique has also taken away the capacity of Alex to make choices, as the prison chaplain realises:
Choice. The boy has no real choice, has he? Self-interest, the fear of physical pain drove him to that grotesque act of self-abasement. Its insincerity was clearly to be seen. He ceases to be a wrongdoer. He ceases also to be a creature capable of moral choice.
This quote comes after a scene where Alex's "cure" is exhibited in front of various individuals, and Alex is forced to endure being beaten by somebody and also a woman tries to seduce him. On both occasions, Alex is unable to respond because he feels too ill. Negative reinforcement has worked to make him feel sick whenever he feels violent, but at the same time, he is now less than a human.