Mind magazine published an article in 1950 "CAN THE MACHINE THINK" which triggered a controversial topic. Alan Turing later proposed an imitation game which was later modified as THE TURING TEST which measures the performance of an allegedly intelligent machine against that of a human being. It is argued to be the best and only standardfor an intelligent behaviour.
THE TURING TEST is a slight variation of the game where a human interrogator communicates with the players(one is human and other is a machine) via a teletype in a closed environment. That means the interrogator is not able to see or speak directly to any one of the players.
A machine passes the test when it is able to fool the interrogator in thinking it is talking to an actual human being and a machine must pass it to be called intelligent(A machine is called intellegent when it is able to adapt to a new situation)