Lecture 8: Operant Conditioning
Behaviourism: Operant Conditioning
• J.B Watson and B.F Skinner revolutionized 20th C psychology.
• Skinner pigeon bomb sight- bomb operated by pigeons, pigeons used to guide missiles to
• His goal was to understand how animals behave and why they behave in the way they do
Edward Thorndike: Thorndike's puzzle box and Law of Effect
• How do we learn a new skill?
• Trial and error used by cat, then practiced recalls it fast
• Behaviour changes because of consequences. They consequence was food received by
solving the puzzle. Later found that just being released is an award for the cat.
• This is called "law of Effect"
• Behaviours that are rewarded get stronger and non-rewarded get weaker.
• Therefore, incorrect behaviours decrease over time
"Learning as error correction"
• Given by Rescorla- Wagner
• Antecedents--> Behaviours --> Consequences
• Not only the consequence is important but also the situation
o Singing in class may not be appreciated vs. while singing in a church choir is
o This "situation" is called antecedents, given by Thorndike
o Situation comes before the behaviour. And depending on that a behaviour is
expressed or suppressed.
o Punishment is not necessary, not being rewarded is enough to weaken a behaviour.
• Error message is generated when a behaviour does not produce correct results.
o E.g. Scratching, hissing, biting won’t open the puzzle box.
o Errors weaken the connection between antecedents and behaviour. Less like to
make the same behaviour over and over if it does not bring results.
• Classical vs. operant conditioning
o In CC, behaviour caused by external stimulus. E.g. Salivating
o In OC, animal selects a behaviour. Behaviour rewarded or not.
o In OC Strength of behaviour= response rate= # of behaviour/unit time.
• Behaviours --> Consequence
• Appetitive stimulus = you like it. E.g.: Pizza
• Aversive stimulus= you have it. E.g.: Electric shock
• What is a reinforcer (reward)?
o Anything that increases behaviour i.e. stimuli that make a behaviour stronger.
o Primary vs. secondary (vs. tertiary)
• Primary: Unconditioned stimuli- reflexive. E.g.: salivating, access to O2
▪ Stimuli that have natural effect on body and mood
• Secondary: Conditioned Stimuli. E.g.. Money
▪ Not natural. We cant eat money but we need it to survive (primary
• Tertiary: e.g.: Like working a job to get money.
• Ways to strengthen behaviour:
o Add appetitive = positive reinforcement
• Like giving a cookie as a award
o Take away aversive = negative reinforcement.
• Not punishing. Like scratching your nose, itch goes way. We are taking way the
itch that is aversive. Taking Aspirin for headache.
• Ways to weaken behaviour
o Take away appetitive = response cost
• Getting grounded, getting a speeding ticket, fines
o Add aversive= punishment
• Inflicting physical pain, yelling
• Punishing like spanking has no effect on internal control
• Behaviour is supressed, not forgotten
• Child does not learn alternative behaviours
• Negative effects:
▪ Increased aggression
▪ Increased likelihood of depression
• Training complex behaviours
o Shaping and successive approximations
o Chaining: chains of simple behaviours that form complex ones.