Motivating operations, MOs, relate to the field of motivation in that they help improve understanding aspects of behavior that are not covered by operant conditioning. In operant conditioning, the function of the reinforcer is to influence "future behavior". The presence of a stimulus believed to function as a reinforcer does not according to this terminology explain the current behavior of an organism – only previous instances of reinforcement of that behavior (in the same or similar situations) do. Through the behavior-altering effect of MOs, it is possible to affect the current behavior of an individual, giving another piece of the puzzle of motivation.