Operant Conditioning

RG 6c

Modified PowerPoint from: Aneeq Ahmad -- Henderson State University. Worth Publishers © 2007

Operant & Classical Conditioning

●Classical conditioning

forms associations

between stimuli (CS

and US).

●Operant conditioning

on the other hand

forms association

between behaviors

and resulting events.

E.L. Thorndike

Law of effect

●responses that produce desirable results will

be learned, or “stamped” into the organism

Yale University

Library

Found that hungry cats in a

puzzle box would work

diligently to solve the puzzle by

trial-and-error to obtain the

food reward outside the box.

Gradually, on succeeding trials,

erroneous responses were

eliminated & effective

responses were “stamped in.”

B.F. Skinner -- Operant Chamber

Using Thorndike's law of effect as a starting

point, Skinner developed the Operant chamber

or the “Skinner box” to study operant

conditioning.

From The Essentials of Conditioning and Learning,

3rd

Edition by Michael P. Domjan, 2005. Used with

permission

by Thomson Learning, Wadsworth Division

Operant Chamber

Operant chamber or Skinner box comes with a bar or key that an animal manipulates to obtain a

food or water reinforcer. It is connected to devices that record the animal’s

responses and allows the researcher to have

complete control over the animal’s environment.

Shaping

Operant conditioning procedure in which

reinforcers guide behavior closer towards target

behavior through successive approximations.

A rat shaped to sniff mines. A manatee shaped to discriminate

objects with different shapes, colors and sizes.

Khamis Ramadhan/ Panapress/ Getty

ImagesFred Bavendam/ Peter Arnold,

Inc.

Types of Reinforcers

Any event that strengthens the behavior it

follows. A heat lamp positively reinforces a

meerkat’s behavior in cold.

Reuters/

Corbis

1.Primary Reinforcer: Innately reinforcing

stimulus that usually satisfy some biological

need like food or drink.

2.Conditioned (Secondary) Reinforcer: Is a

learned reinforcer. It gets its reinforcing power

through its association with primary reinforcer. Examples…

Grades, praise, smiles of

approval and applause

Primary & Secondary Reinforcers

1.Immediate Reinforcer: A reinforcer that

occurs closely to a behavior in time. Rat gets

a food pellet for a bar press.

2.Delayed Reinforcer: A reinforcer that is

delayed in time for a certain behavior. A

paycheck that comes at the end of a week.

Immediate & Delayed Reinforcers

We may be more inclined to engage in small immediate

reinforcers (watching TV) than large delayed reinforcers

(Getting A in a course) which requires consistent study.

1.Positive Reinforcement: Increase in response by

adding/giving a positive stimulus Getting $5 for each A on your report card

Giving candy for every right answer in class

2.Negative Reinforcement: Increase in response

by removing an aversive (negative) stimulus Taking aspirin to relieve a headache

Faking an illness to avoid going to school

Using an umbrella to keep from getting wet

Positive & Negative Reinforcers

Add

Subtract

Add what?

Subtract what?

Reinforcement Schedules

1.Continuous Reinforcement: Reinforcing the

desired response each time it occurs. Needs

to be used when initial learning is taking

place

2.Partial (Intermittent) Reinforcement:

Reinforcing a response only part of the time.

Though results in slower acquisition in the

beginning, shows greater resistance to

extinction later on.

Ratio Schedules

Fixed-ratio schedule: Reinforces a response only after a specified number of responses

ex: piecework pay, reward cards (buy 10, get one free)

Variable-ratio schedule: Reinforces a response after an unpredictable number of responses. Produces more responding than any other method and is hard to extinguish because of unpredictability.

ex: gambling

Interval Schedules

Fixed-interval schedule: Reinforces a response only after a specified time has elapsed

ex: studying for an test the night before or getting paid every two weeks

Variable-interval schedule: Reinforces a response at unpredictable time intervals, produces slow steady responding

ex: pop quiz, fishing, stargazing

Schedules of Reinforcement

Let’s review…

●Reinforcer/reinforcment

●Primary reinforcer

●Secondary reinforcer

●Positive reinforcement

●Negative reinforcement

●Intermittent schedules of reinforcementoFixed-ratio

oVariable-ratio

oFixed-interval

oVariable-interval

Punishment

An aversive event that decreases the behavior

that it follows.

Give –

Take away + omission

training

Punishment

1.Punishment can result in unwanted fears.

2.Conveys no information to the organism.

3.Justifies pain to others.

4.Unwanted behaviors reappear in its absence.

5.Aggression towards the agent or aggression

seen as “ok” or “right.”

6.One unwanted behavior appears in place of

another.

Although there may be some justification for

occasional punishment (Larzelaere & Baumrind,

2002), it usually leads to negative effects.

Cognition & Operant ConditioningEvidence of cognitive processes during operant learning comes from rats during maze exploration, where they navigate it without an obvious reward.

Edward Tolman found that the rats seemed to develop cognitive maps or mental representation of the layout of the maze (environment) b/c if blocked the “normal” route, the rat found an alternate path

●the detour would be the shortest path around the barrier, even though the rat had not been reinforced for that alt. short path

●brain imaging points to the hippocampus a the structureinvolved in “drawing” the cognitive map

Latent Learning

Such cognitive maps are based on latent

learning which is learning that occurs without

reinforcement, but becomes apparent when an

incentive is given (Tolman & Honzik, 1930).

Tolman allowed rats to freely wander

the maze for several hours…when the

rats were later offered a reinforcement,

the ones who “wandered around” ran

through the maze more quickly than those

who had not been in the maze

Biological Predisposition

Biological constraints predispose organisms to learn associations that are naturally adaptive.

Breland and Breland (1961) showed that

animals drifted (instinctual drift) towards

their biologically predisposed instinctive

behaviors.

Marian Breland Bailey

Photo: Bob

Bailey