As Caesar was brought around Ape Management in preparation for his conditioning in 1991, he saw a Keeper training a gorilla to obey the 'no' command by giving him electric shocks when the word is spoken. It is possible that this same person was the keeper who administered the shock treatment to Caesar to force him to talk, and who was subsequently killed by Caesar.
- In the film's novelization, a scientist named 'Dr. Bowen' supervises the 'No' conditioning of the apes.
- The man who tortures Caesar is named 'Johnny' in Marvel Comics' adaptation, and 'Dr. Chamberlain' in the film's novelization.
- The 'No' conditioning was permanently seared into the minds of the unfortunate apes - many years later Aldo was visibly shocked when Abe the Teacher accidentally used the word. Humans had been banned from using the word by Caesar, but apes could still say no to each other and humans.