(plural: automatons or automata)
a person who acts or reacts without feelings or thought as if he/she were a machine, i.e. just reacts mechanically;
Consumer culture, i.e. buying and spending money of consumers, turns many intelligent people consumer automatons. (from sentence.yourdictionary.com)
Mary is an automaton; nothing in this world excites her
My assistant is such an automaton that he does not even bother to show his feelings when he does not like my ideas; he just follows my instructions!