Establishing an association (in time) between stimuli that precede reinforcement and the reinforcing event. For example, a rat is placed in an operant chamber and a microcomputer periodically turns on the feeder. When the feeder is turned on, it makes a click and a food pellet falls into a cup. Because the click and the appearance of food are associated in time you would, after training, observe a typical rat staying close to the food magazine and quickly moving toward it when the feeder is operated.