L&B Lec 5 (Operant Conditioning)

How did Skinner define operant conditioning?

1) a behavior will be repeated by the subject when rewarded

2) repetition leads to reinforcement and

3) reinforcement to changes in behavior

he demonstrated that whole chains of behaviors can be built step by step

What are the 3 basic variables of operant conditioning?

1) behavior

2) consequence

3) discriminative stimulus (person that sets the stage ex. parent)

Role of discriminative stimulus? (antecedent)

• a stimulus that signals that the behavior and the reinforcement contingency is in effect

• An example that we used in the video was the bar serving as the discriminative stimulus that the rat must press the bar (Response) to receive food (Outcome).

• These variables relate directly to what Skinner proposed to explain the relationship between the environment and behavior: S(R-O) theory S- for stimulus R- for response O- for outcome or consequence

• A discriminative stimulus has control over a specific behavior. Why? because, in the past, the behavior was reliably reinforced in the presence of that stimulus. (reinforced or punished)

• Another Way to look at it is the ABCs of behavior: A=antecedent, B= behavior and C= consequence

• “Sets the stage for behavior”

Role of consequence?

A consequence highlights the probability of that behavior taking place in the presence of the discriminative stimulus. If the behavior is reinforced, it increases the likelihood of that behavior happening in the future amid that discriminative stimulus.

If the behavior is punished or ignored, then it decreases the likelihood of that behavior happening in the future amid that discriminative stimulus.

Be familiar with the “reward and motivation in learning” video?

• Demonstrated the importance of “Drives”; that the organism needs to be motivated to act for learning to take place. The hungry animal learns the response that is rewarded by food and simultaneously reduces its hunger drive. VERY IMPORTANT RELATIONSHIP: “A motivated animal will learn any response that is promptly followed by a reduction in the strength of the drive”. (e.g., removal of a shock)

• Definition of Motivation: an internal state that propels individuals to engage in goal-directed behavior

• In other words, B.F. Skinner states that motivation to do anything is a direct function of the variables or conditions that the organism is subjected to. In this case, food deprivation. This is how he defined motivation objectively

• The video also demonstrated an example of a learned social response. For example, responding to another animal by striking him can also be learned. In this case, the striking behavior is being reinforced by the removal of the shock, or via negative reinforcement (the removal of a negative or aversive stimulus in response to a specific behavior). Over time, the target behavior should increase in nature with the expectation that the unpleasant stimulus will be removed. In other words, the organism learns to engage in specific behavior to avoid a negative outcome.

• It’s interesting to note that when a drive is supplied, the satiated animal learns more quickly than the hungry one did. This is because the drive produced by electric shock is stronger than hunger. And can be reduced more quickly and completely. So, differences in drive lead to differences in learning. This demonstrates that the satiated rat is not innately lazy, all it needed was a little motivation to learn a behavior.

Notes on Skinner’s classroom demonstration video Pt.1

• “The pigeon is always right. Whatever the pigeon does today will be because of the conditions that we have arranged for it. If things don’t work out, it would be my fault for not arranging the proper conditions”

• The effect of the environment on the organism has not been fairly understood.

• the first evidence that the environment did something to the organism rather than just vice versa was the conditioned reflex (the conditioned response)- something happens in the environment, and the organism responds...that gave rise to S-R psychology or S-R theory or classical conditioning.

• The consequences of behavior are as important as its antecedents. A consequence is what follows a behavior.

• Things happen to an organism after it behaves and has a very important effect on it. The effect (or the consequence) is to make it more likely that the organism will behave in the same way again. And this is what is called operant conditioning.

• According to Skinner, food to a hungry organism is a reinforcer. A reinforcer is simply defined by its impact on behavior. For example, if there is an increase in pecking behavior, then food is automatically serving as a reinforcer.

Notes on Skinner’s classroom demonstration video Pt.2

• Skinner demonstrated how shaping can be used to establish a target behavior (i.e., turn counterclockwise).

• Demonstrated how the same response will or will not be made to a “given stimulus” (i.e., discriminative stimulus) based on consequences.

• He used differential reinforcement; that means he reinforced some behaviors and subjected other behavior to extinction to shape the target behavior into existence.

• We learned about extinction in classical conditioning (breaking the association between the CS and the UCS to suppress the behavior).

• In operant conditioning, extinction serves the same purpose which is to extinguish an operant response by omitting its reinforcement. For example, Skinner reinforced the pigeon only when the light was off (dark key)- making that key a discriminative stimulus while promoting extinction to the lighted key.

• IMPORTANT: As you can see, Skinner manipulated the pigeon’s antecedents and consequences to shape and control its behavior.

How did the pigeon learn to discriminate between the dark and lighted key?

• According to Skinner, not by forming discrimination internally nor by any rational process per say. It’s all a product of one stimulus (dark key) now controlling the response and the other stimulus (light key) does not.

• In other words, the discrimination process is in the apparatus (i.e., the environment) and not in the pigeon’s head.

• NOTE: Something very interesting that Skinner stated earlier in the video is the fact that the pigeon is not partaking in random responses, but motor responses in respect to the environment. In other words, in respect to the environmental conditions and manipulations.

How does Skinner define an operantly conditioned response?

• An operant conditioned response is emitted by the organism, instead of being elicited by the environment (as in classical conditioning).

• Even though an operant response is perceived as voluntary in nature, that behavior is in fact shaped and controlled by the environment. More specifically, that behavior is shaped and controlled by its antecedents and its consequences.

• That’s what Skinner meant when he said that we are nothing but a locus- a point in time shaped and molded by various antecedents and consequences.

• (Bio + Env) = Behavior (followed by consequences which further shapes that behavior)

Positive reinforcement

Once the response takes place, it is followed by the introduction of a positive stimulus.

Example: dog sits, you give it a treat!

negative reinforcement?

Once the response takes place, it is followed by the removal of a negative stimulus.

Example: by going to traffic school, that removes the speeding ticket from your record

Positive punishment

(meant to decrease negative behavior)

Once the response takes place, it is followed by an unpleasant stimulus.

ex. You commit a crime you go to jail.

Negative Punishment

Once the response takes place, it is followed by the removal of a positive or wanted stimulus.

Ex. you break curfew, no car for a month.

Define Continuous reinforcement?

When is it used?

• Reinforcement is given after every response

• When the response is initially acquired or taught

define schedules of reinforcement?

when are they most efficient?

• They determine “when” and “how often” a reward is given.

• To maintain the behavior

Define Fixed Ratio?

reinforcement after a fixed number of responses

Variable Ratio

reinforcement after unpredictable number of responses.

How is extinction defined in operant conditioning?

withholding the reinforcement to extinguish a learned response.

what is the relationship between schedules of reinforcement and the extinction process?

• schedule of reinforcement will determine how long it will take for a behavior to be extinguished.

• If a behavior is reinforced on a variable ratio, it takes longer to extinguish than if behavior is reinforced on a fixed ratio.

• But in the long run, all behaviors are capable of being extinguished.

what is extinction burst?

This is when someone experiences a sudden and temporary increase in response frequency/intensity and variability.

(Things will get worse before they get better)

impact of occasional reinforcement during extinction?

It will make the behavior more resistant to extinction.

(it will make it harder to extinguish)

fixed interval

reinforcement after a fixed amount of time

What is one characteristic of fixed interval schedule?

You must keep in mind that the interval determines when the reinforcer is available, not when it is delivered

Variable Interval

reinforcement after an unpredictable amount of time

Which schedule is most effective in promoting a response?

Ratio schedule: the more you respond, the more you are reinforced (unlimited reinforcement).