Video Lecture Psych 1X03
Chapter 3: Classical Conditioning
Instrumental Conditioning 1
Classical Conditioning – organisms learn the contingencies between biologically important stimuli and events;
can occur in the absence of overt training – simply presenting together two biologically important stimuli leads
to their association
Instrumental Conditioning – involves explicit training between voluntary behaviors and their consequences;
learning contingency between behaviors and their consequences
Edward L Thorndike experiment
o Cats in a puzzle box (small chamber with a door that could be opened by performing a specific behavior
such as pulling a rope), outside the box was a small dish of food that provided motivation for the
hungry cat to escape
o Over several trials, the cat was placed in the puzzle box as Thorndike carefully observed their behaviors
and recorded their escape time
o At first, the hungry animal would engage in random behavior – it would happen upon the correct
solution (pulling the string)
o Prediction: The cat would escape immediately when placed in the same puzzle box, once it had
discovered the solution the first time
o Reality: Frequency of random behaviors gradually decreased over time – never a distinct “aha”
moment
o Rope pulling behavior – stamped in
o Random behavior – stamped out
Law of Effect: behaviors with positive consequences are stamped in, those with negative consequences are
stamped out
Four Consequences
Behavioral responses are changed by both positive reinforcers and negative reinforcers, each of which can
either be presented or removed
Reward Training – presentation of a positive reinforcer; behavior is likely to increase
o Eg/ For every A grade Billy receives, he is given $5
Omission Training – Removal of a positive reinforcer; behavior is likely to decrease
o Eg/ Time Out
o Eg/ IF Billy fails a test, he doesn’t get any dessert that night
Punishment – presentation of a negative reinforcer; behavior is likely to decrease
o Can be controversial, must consider ethics
o Eg/ If Billy fails English, he will have to cut the grass every week in the summer
Escape Training – removal of a negative reinforcer; behavior is likely to increase
o Eg/ Rat Cage – one side delivers an electric shock, shock can be avoided by staying on the other side of
the cage
o Eg/ When Billy gets a good report card, he doesn’t have to do his chores for a week
Punishment ≠ Omission
Instrumental conditioning proceeds best when the consequence immediately follows the response
Contingencies
Classical Conditioning – the process of acquisition, in which an organism learns the contingency between a
stimulus and a biologically important event
Instrumental Conditioning – the process of acquisition, which leads to learning the contingency between a
response and its consequences
o Researchers often measure the rate of responding to the new behavior
Using a cumulative recorder; long piece of paper flows through the machine at a constant rate
as a pen draws a straight line – which each response made by the subject, the pen moves up a
notch leading to a characteristic patter of acquisition
Flat horizontal line – indicates when the subject is not responding Video Lecture Psych 1X03
Upward slope – indicates when a response has been made
The pattern of responding depends on a number of factors including the subject, the complexity
of the behavior and type of reinforcement used
AutoShaping
AutoShaping – behaviors can be learned without explicit training guided by a researcher
o Eg/ Pigeon, peck keyhole and sand falls down, eventually stop pecking keyhole
Not all behaviors can be AutoShaped
Rewards some behavior that night occur spontaneously
Shaping
Complex behavior can be organized into smaller steps which gradually build up to the full response we hope to
condition – each step can be reinforced through reward training
o Eg/ Pigeon Ping-Pong; Peck ping pong table peck stationary ball peck moving ball peck moving
ball to across the table
Rewards successive steps towards a behavior that the one wouldn’t normally do
Instrumental Conditioning 2
Generalization and Discrimination
Discriminative Stimulus – signals when a contingency between a particular response and reinforcement is “on”
o Eg/ Child who is rewarded with a treat for eating his vegetables at home, but isn’t rewarded at his
grandparents house
Environment of his home – SD for the response of vegetable eating behavior, which is reinforced a with
access to a dessert reward
o Eg/ Pigeon pecks at keyhole and receives food
Green light is on – indicates that food will be received SD
S delta (δ)– a cue which indicates when the contingent relationship is not valid
o Eg/ Environment of the grandparents home becomes an Sδ for he response of vegetable eating, child
will learn that under these conditions, eating vegetables will not lead to a dessert reward
o Eg/ Pigeon keyhole
Green light off, clicking sound on Sδ
SD Generalization Gradient – similar stimulus to the SD, the farther you get from the original stimulus, the less
response
o Eg/ Pigeon keyhole
Bird learns to respond to green light with pecking the keyhole
Bird will also peck with lights of similar wavelength to the original SD
Extinction
o Eg/ Sarah’s parents reward Sarah with praise and attention when she is polite, but as her parents get
busier, they are unable to pay as much attention to her – Sarah may stop responding with polite
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