Operant Conditioning Part 2

Operant ConditioningA method of learning that occurs through reinforcements

and punishments for behavior. We learn to perform certain behaviors more often because they result in

rewards, and learn to avoid other behaviors because they result in punishment or adverse consequences.

Operant Conditioning

Experiences shape our future behavior choices, even if we don’t realize

it is happening.

“Punishment” is something bad happening to you.

“Reinforcement” is something good happening. Remember,

“Negative” means something is taken away, and “Positive” means

something is added to the environment.

Types of Reinforcement/Punishment

Rational

MoneyFood

Things

Emotional

EncouragementAttention

Love/Affection

Keep in mind that not all rewards are physical things. Even a smile can be enough reinforcement to encourage a

behavior to continue. Think of what might occur if you lost or gained the items listed below.

B. F. Skinner

Lived 1904-1990. Influential American psychologist considered

to be one of the founders of behaviorism (along with Watson

and Pavlov). He identified the principles behind operant

conditioning, and was the first to study the behavioral effects of

punishment and reinforcement in highly controlled experiments.

The Skinner BoxSkinner’s operant conditioning chamber (also called a

Skinner Box) was designed to teach rats how to push a lever. This behavior is not natural to rats, so operant conditioning with positive and negative reinforcement

were performed in order to teach the behavior.

Positive Reinforcement:A rat was awarded with food when he pressed the lever.

Negative Reinforcement:A rat was able to turn off

electric shocks produced by the floor by pressing the lever.

Positive Reinforcement• Initially, the rat’s behavior

was random. It accidentally tripped the lever and a food pellet was released.

• The rat soon discovered that intentionally pressing the lever resulted in a reward.

• The consequence of performing the behavior (lever press) was desirable, ensuring that the rat would repeat the action.

Negative Reinforcement

• An unpleasant electric current ran through the floor of the rat’s cage.

• Initially, accidental lever pushing turned off the electric current.

• The consequence of avoiding something painful (removal of an unpleasant stimulus) ensured that the rat continued to push the lever.

Variable Schedule of Reinforcement

Skinner learned that behaviors become the most frequent when rewards are not given on a consistent schedule. Rather, rewards that are given at variable

times cause behaviors to increase greatly.

Wow! Slot machines are so

addictive!

Schedules of Reinforcement

Continuous Schedule of Reinforcement

Every time a behavior is performed, a reward

is given.

(When first teaching a behaviour, this schedule helps the subject learn quickly.)

Variable Reinforcement Schedule

Behavior is reinforced/rewarded at random (unpredictable) times.

(In the long-run, this schedule causes the subject to perform the behavior more

often, and remember it for longer.)

ShapingTo achieve a desired behavior, step-by-step trials are used to direct the participant towards the end goal.

Skinner noticed that the pigeons in the skinner box were not accidentally

pushing the button that would release food. How could he teach the pigeon

that pressing the button would result in a positive outcome?

In other words: breaking down behavior into small steps, and giving positive reinforcement along the way can result in the learning of more complex behaviors.

ShapingStep 1: give the pigeon

food when it turns toward the button.

Step 3: give the pigeon food when raises its head to the height of

the button.

Step 2: give the pigeon food when it walks toward the button.

Step 4: give the pigeon food when it taps the button with its beak.

Shaping: What else can we train the bird to do?

“We first give the bird food when it turns slightly in the direction of the spot from any part of the cage. This increases the frequency of such behavior. We then

withhold reinforcement until a slight movement is made toward the spot. This again alters the general distribution of behavior. We continue by reinforcing

positions successively closer to the spot, then by reinforcing only when the head

is moved slightly forward, and finally only when the beak actually makes contact

with the spot. ...In this way we can build complicated operants which would never appear in the repertoire of the organism

otherwise.”

Video 1

ShapingSkinner was able to teach pigeons many complex behaviors - such as telling the difference between different words and knocking bowling pins over with a miniature bowling ball.

The technique did not work equally on all animals. Raccoons, for example,

thought the ball itself was food, and did not cooperate

in the experiment!

Shaping HumansEXAMPLES

Learning to write. You might begin by tracing letters. Next, by connecting dots

or dashes. Next, by looking at letters and copying them below. Finally, by writing the letters from memory.

Learning to eat with a spoon. First you need to pick up the spoon. Next you need to put the spoon in the bowl. Next you need to scoop the food into the spoon. Next you need to lift the spoonful out of the bowl.

Finally, you need to put the spoon into your mouth. Encouragement from parents along the way can reinforce these movements.