The torturer wanted him to say that there were five lights as that would be a signal that Picard was now accepting the torturer's reality. It's based off a conc

The torturer wanted him to say that there were five lights as that would be a signal that Picard was now accepting the torturer's reality. It's based off a concept from Orwell's 1984, where another torturer says that they can make someone believe 2 + 2 = 5. Also, Asch's “Line Experiment” where people conform against their own perception.