Association was a psychological term for the mental connection that an individual created.
In the mid-2270s, while aboard the USS Enterprise, Commander Willard Decker introduced the Ilia probe to the light cube table in the recreation deck. This was a game that Ilia enjoyed playing and nearly always won it. He played the game with the probe watching; she played the game and her expression showed a glimmer of recognition. Doctor Leonard McCoy, watching from Captain James T. Kirk's quarters, thought that Decker was making progress by using audial-visual association. (Star Trek: The Motion Picture)