1. Learning
Ch. 5

2. Ivan Pavlov – scientist who discovered theory of classical conditioning

3. Learning: process that produces an enduring change in behavior or knowledge as a result of past experience
Conditioning: the process of learning associations between environmental events and behavioral responses
very basic form of learning

4. Classical Conditioning
Ivan Pavlov – scientist who discovered theory of classical conditioning
was investigating the role of saliva in digestion when he came across the phenomenon of dogs salivating before he put the food on their tongue
He noticed that the reflex (salivation) occurred before the stimulus (food) was presented

5. He discovered that a new, learned stimulus elicited the salivary response
Thus in classical conditioning, a subject learns an association between two stimuli
Classical conditioning involves pairing of a neutral stimulus (the sight of Pavlov) with an unlearned, natural stimulus (food in the mouth) that automatically elicits a reflexive response (the dog salivates)

6. If the two stimuli (Pavlov + Food) are repeatedly paired, eventually the neutral stimulus (Pavlov) elicits the same response as the natural stimulus (food), even in the absence of the natural stimulus
So the dog formed a learned association between the sight of Pavlov and the food

7. Classical Conditioning Terms
Unconditioned stimulus (UCS) – natural stimulus that reflexively produces a response without prior learning (food in the dog’s mouth)
Unconditioned response (UCR) – unlearned, reflexive response elicited by the UCS (dog’s salivation)

8. Conditioned stimulus (CS) – stimulus that is originally neutral, but comes to elicit a reflexive response (sound of the bell)
Conditioned Response (CR) – learned, reflexive response to previously neutral stimulus (dog’s salivation to the sound of the bell)
Figure 5.1 on p. 193

10. Operant Conditioning
Form of conditioning that explains how we acquire and maintain voluntary behaviors
(classical conditioning involves reflexive behaviors)
Also called Skinnerian conditioning, which explains learning as a process where behavior is shaped and maintained by its consequences

11. One possible consequence of a behavior is reinforcement
Reinforcement is said to occur when a stimulus or an event follows an operant (active behavior) and increases the likelihood of the operant being repeated
Reinforcement is defined by the effect it produces—increasing or strengthening the occurrence of the behavior in the future

12. Example:

13. Training a mouse to press a lever, which releases the food
They learn that pressing the lever provides them with food (reinforcement)
Pressing the lever is the operant-the active response. The food is the reinforcing stimulus – the stimulus or event that is sought in a particular situation

14. Another Example
You put money in the vending machine and press the button……..nothing happens. You push the button again…….nothing. You try the coin release……..nothing. Finally, you bang on the machine and the drink drops down.
In the future, if pressing the button doesn’t work what are you likely to do?

15. Banging on the vending machine is the operant – the active response you emitted
The soft-drink is the reinforcing stimulus—the stimulus or event that is sought in a particular situation
A reinforcing stimulus is typically something desirable, satisfying or pleasant

16. Positive and Negative Reinforcement
Skinner did not use positive or negative in their everyday sense, meaning “good” and “bad”
Instead, think in mathematical terms. Positive = something added (+), Negative = something subtracted, or removed (-)

17. Positive Reinforcement involves following an operant with the addition of a reinforcing stimulus
A response is strengthened because something is added or presented
Ex: you attend a school play and write a short paper about it (the operant) for 20 bonus points (the reinforcing stimulus) in literature class

18. If the reinforcing stimulus has the effect of making you more likely to repeat the operant in similar situations in the future, then positive reinforcement has occurred

19. Negative reinforcement involves an operant that is followed by the removal of an aversive stimulus.
A response is strengthened because something is being subtracted or removed
Ex: taking two asprin (the operant) to remove a headache (the aversive stimulus)
Aversive stimuli – physical or psychological discomfort that an organism seeks to escape or avoid

20. Primary reinforcer - naturally reinforcing for a given species (ex
Primary reinforcer - naturally reinforcing for a given species (ex. Food, water, warmth, etc.)
Conditioned reinforcer (secondary reinforcer) – has acquired reinforcing value by being associated with a primary reinforcer
Ex: Money – money is not reinforcing in and of itself, its reinforcing because we’ve learned that we can use money to acquire primary reinforcers (food, money, clothes, etc.)

21. Punishment

22. Punishment: process in which a behavior is followed by an aversive consequence that decreases the likelihood of the behavior being repeated
Different from negative reinforcement (negative reinforcement always increases the likelihood of the operant being repeated in the future; punishment decreases the likelihood of the operant being repeated)

23. Punishment by application (positive punishment): a response is followed by the presentation of an aversive stimulus
“Positive” infers that something is added or presented in the situation
Ex: your cell phone rings during class (the operant) and you are reprimanded by the teacher (the punishing stimulus) is added

24. Punishment by removal (negative punishment)
“Negative” indicates that some stimulus is subtracted or removed from the situation
Negative punishment is the loss of a reinforcing stimulus following a behavior
Ex: because he was flirting with another woman (the operant), a guy gets dumped by his girlfriend (loss of reinforcing stimulus)

25. Shaping and Maintaining Behavior
Skinner Box: small cage with a food dispenser. Attached is a device that records the number of operants made by an experimental animal (rat pressing the lever)
Shaping: reinforcing successively closer approximations of a behavior, until the behavior is displayed
Ex: reinforcing the rat with a food pellet whenever it moves close to that half of the skinner box with the lever (other responses are ignored)

26. Once that response has been learned, reinforcement is held until the rat moves even closer to the bar…….then the rat might be reinforced only when it touches the bar
Step by step, the rat is reinforced for behaviors that correspond even more closely to the final behavior (pressing the bar)
This is shaping

27. Skinner believed that shaping could explain how people acquire a wide variety of abilities and skills ex: learning to tie shoes, learning sophisticated computer programs
Once a rat had acquired a bar pressing behavior, Skinner found that the most efficient way to strengthen the response was to immediately reinforce every occurrence of bar pressing
This pattern of reinforcement is called continuous reinforcement

28. In everyday life however, it’s more common for responses to be reinforced only sometimes, this is called partial reinforcement
Ex: shooting free throws: you don’t make every shot, sometimes you’re reinforced by making a shot and sometimes you’re not
If you never made a shot, you’d probably quit basketball. This is an example of extinction

29. Extinction: In operant conditioning, when a learned response no longer results in reinforcement, the likelihood of the behavior being repeated gradually declines
Partial reinforcement effect: partially reinforced behaviors tend to be more resistant to extinction than are behaviors using continuous reinforcement
Ex: Skinner (pigeon pecking disk 100 times on continuous reinforcement schedule before extinction vs times on partial schedule)

30. Schedules of Reinforcement
Skinner found that specific preset arrangements of partial reinforcement produced different patterns and rates of responding
Fixed Ratio (FR) Schedule: reinforcement occurs after a fixed number of responses
Ex: rat on a 10-to-1 fixed-ratio schedule (FR-10), would have to press the bar 10 times in order to receive one food pellet
Ex: piecework – being paid $1 for every 100 envelopes you stuff – is an example of an FR-100 schedule

31. Variable Ratio (VR) Schedule: reinforcement occurs after an average number of responses, which varies from trial to trial
Ex: a rat on a VR-20 schedule, might have to press the bar 25 times on the first trial before being reinforced and 15 times on the second trial

32. Fixed-Interval (FI) Schedule: a reinforcer is delivered for the first response emitted after the preset time interval has elapsed
Ex: a rat on a 2 minute fixed interval schedule (FI-2) would receive no food pellets for any bar presses made during the first 2 minute. The first bar press made after the 2 minute interval would be reinforced

33. Variable Interval (VI) Schedule: reinforcement occurs for the first response emitted after an average amount of time has elapsed, but the interval varies from trial to trial
Ex: a rat on a VI-30 seconds schedule might be reinforced for the first bar press after only 10 seconds have elapsed on the first trial, for the first bar press after 50 seconds on the second trial and after 30 seconds on the third trial. This works out to an average of one reinforcer every 30 seconds