You often hear that a student who reads the assignment to get a good grade is extrinsically motived, and one who doesn’t care much about the grade is intrinsically motivated. Similar language describes the behavior of athletes, professionals, and just about everyone making an effort. Generally, it is considered better to be intrinsically motivated, lest one be accused of shallowness or lacking in persistence.
There is no such thing as intrinsic motivation.
When we can identify a reinforcing consequence or schedule that maintains a behavior, we use the extrinsic label. When we can’t identify the reinforcing consequence or schedule, we use the intrinsic label. It’s that simple.
Nothing anyone does in relation to a soda machine will be labeled intrinsic motivation. The person can joyfully feed quarters into the slot, poetically describe the sound of the coins dropping into the mechanism, and dance circles of ecstasy after each quarter is deposited; we know she wants a soda. But the same person reading a book for school, delightedly turning pages, sharing well-written passages with her roommate, and cherishing the book itself appears to be intrinsically motivated when we have good evidence that she doesn’t care too much about the grade. Rather than look for other reinforcers, we invent an internal explanation (she loves learning).
Schedules of reinforcement are also important. If someone puts quarters in a slot machine, he will be rewarded, largely or minutely, at random and often enough to create a persistent behavior. The soda machine provides a soda nearly every time. If he walks into a casino, puts a dollar in a slot machine, and nothing comes out, he will not be too upset, even though he just lost out on a payout of $100,000. If he then walks over to the soda machine and puts in a dollar and nothing happens, he will bang the machine, maybe kick it, and pull the coin return lever several times, even though he only lost out on a soda. If a behavior is consistently reinforced, extinction is quick (and experienced as frustration). That’s why you get mad at your loving spouse more quickly than at your officemate when neither notices your new shirt or your clever remark. When behavior is reinforced intermittently, as in a casino, it takes a lot of failures before you stop trying (extinction is slow), and the process is experienced more as despair or longing than frustration.
A stranger to the situation would describe the person at an unyielding soda machine as extrinsically motivated by whatever’s in the machine and the person at an unyielding slot machine as intrinsically motivated since the person doesn’t seem to expect anything from the machine.
The main reason we can’t identify reinforcers, according to Skinner, is because it is undignified to get caught working for a reward. Erving Goffman and Keith Johnstone would say it is undignified because it is something that children can’t avoid, and adults get status-enhancement (Johnstone) or avoid stigma (Goffman) by acting in ways that children can’t. Children obviously stare at the cake all through dinner and wolf down their dessert. Adults lose face if they get caught doing either. The name for the mutual agreement to disguise our motivations at dinner is “table manners.” (I acknowledge that “table manners” also describes behavior that makes the meal more appetizing to other diners.)
The main problem with the concept of intrinsic motivation is that it doesn’t give the teacher much to do to build skills. Mainly, the concept makes teachers shame students who reveal what reinforces their behavior. But if teachers know which reinforcers are effective, they can use the knowledge by arranging for the reinforcement to depend on approximations of the skills that will serve the student later. Or the teacher can create conditioned reinforcers by associating, say, passing the ball with, say, winning to create a reinforcer the teacher can control.