Operant conditioning NARRATOR: Can pigeons read? This one gives every indication. Because he's been taught to distinguish between two words and to behave appropriately. He's learned his different response to each sign by being rewarded with food. So the bird isn't acting independently. Its behavior is shaped by controlling its environment. The first task was to isolate an individual piece of behavior and see how that could be changed. Skinner did this by keeping individual pigeons at about 3/4 of their normal weight, so that the birds were always hungry. And food could be used as an automatic reward. The pigeon was studied in a uniform box, one it quickly grew used to. One piece of behavior, pecking a colored disk, was measured on a graph. The pigeon learned that pecking the disk produced a reward. Then, the behavior of pecking could be studied in relation to how often that reward was offered, or in Skinner's terms, what was the schedule of reinforcement. RESEARCHER: The main thing is what we call schedules of reinforcement. Reinforcement is what the layman calls reward. And you can schedule that, so that a reward occurs every now and then when a pigeon does something. We usually use a wristwatch with a pigeon pecking a little disk, a little spot on the wall. And you can reinforce it with food. But we don't reinforce every time, you have to every 10th time, or perhaps only once every minute, or something like that. There are a very large number of schedules. And they have their special effects. There is a good example of how you can move from the pigeon to the human case. Because one of the schedules, which is very effective with rats or pigeons, is what we call a variable ratio schedule. And that is at the heart of all gambling devices and has the same effect. The pigeon can become a pathological gambler, just as a person. Now, the fact that we found that out with pigeons and could prove it, by removing and changing the schedule, makes it easy for us to interpret the case with human subjects. We don't say that the human subject gambles to punish himself, as Freudians might say, or he gambles because he feels excited when he does so, nothing of the sort. People gamble because of the schedule of the reinforcement that follows. And this is true of all gambling systems. They all have variable ratios built into them. So what we've learned from the pigeon made it possible to interpret this vast field very effectively. NARRATOR: Where does that leave freewill? Because we all have a choice whether to do things or not to do things. RESEARCHER: Yes, well you see, we leave it in the possession of a fiction. We have assumed, somehow or other, that these internal states, feelings, and so on have initiated something, they have started something, they have created. We have done something in a voluntary way. We have willed to act. If you now look at the actual history, we find that there are external reasons why this has happened. In other words, by discovering the causes of behavior, we can dispose of the imagined internal cause. We dispose of free will as an American divined of the 18th century, Jonathan Edwards, did. He said, we believe in free will because we know about our behavior, but not about his causes. And of course, it's the object of a science of behavior to discover causes. And once you have found those causes, there is less need to attribute to an internal act of will. And eventually, I think we need to attribute nothing to it.