In Chapter 4 of Brave New World by Aldous Huxley, how does the episode in the elevator portray the robot-like characteristics of the lower-caste workers?
In Chapter 4 of Brave New World, the Epsilon-Minus Semi-Moron's robot-like characteristics are depicted by his utterance of only one word, his stupor, and by his having been programmed to respond to the bell and mechanical voice that emanates from the lift.
As Lenina steps into the lift (elevator) she notices that it is crowded with men who have come from the Alpha Changing Rooms, many of whom she has dated. She sees Benito Hoover, and then she notices Bernard Marx, to whom she speaks. But, at no time is there any verbal engagement with the Epsilon-Minus because he is simply a creature engineered for a simple function. As the lift comes to the top of the building, a "creaking voice" calls out "Roof!" When the sunlight and the "glory of the afternoon" strikes the Epsilon, he is startled and blinks his eyes.
"Oh, roof!"...He was as though suddenly...awakened from a dark annihilating stupor. "Roof!"
After everyone walks off the lift, the Epsilon, who has only the one single thought in reaction to the sunlight upon him, stands stupefied until a bell rings and a loud speaker bellows orders to him: "Go down,...go down. Floor Eighteen. Go down, go down. Floor Eighteen. Go down, go...." The "liftman" shuts the doors and presses the button for the appropriate floor. He, then,
...dropped back into the droning twilight of the well, the twilight of his own habitual stupor.
The elevator operator's features are described as "monkey like" indicating the low evolutionary position of the lower caste worker. "He" responds mechanically to the sun, cheered, presumably, by its warmth. But "he" has no desire to remain there because he has been trained to do a simple task --- operate the elevator, and that is what he does, and it won't function well if it stays at the top floor in the sun. (Interestingly, in our world he has been replaced by an even "lower" caste --- an electronic system which does what he does and makes even fewer demands on the system than the operator does. Of course, perhaps lower caste workers assemble the elevator mechanism.)
This is a clear example of how beings in their society are "bred" for one task, a task they do without complaining and, supposedly, without error.