PSYC2050 WEEK 5

CLASSICAL VS OPERANT CONDITIONING

Classical: 

• Ivan Pavlov 

• Leaning via association 

• Relies on the formation of reflexive associations between stimuli resulting in involuntary responses 

Operant: 

• B.F. Skinner 

• Learning via reinforcement 

• Relies on the consequences of past actions influencing future behaviour, resulting in an increase or decrease of voluntary behaviour 

OPERANT CONDITIONING PRINCIPLES

Consequences lead to changes in voluntary behaviours 

• A behaviour that results in a reward tends to be repeated or become more frequent 

• A behaviour that results in a punishment tends to be avoided or become less frequent 

THE LAW OF EFFECT

The tendency to perform an action is increased if rewarded, weakened if not.  

SKINNER BOX

SHAPING

Selectively reinforce behaviour that resembles the desired target behaviour. 

SHAPING IN THE REAL WORLD

• No experimenter/trainer 

• Real-world reinforcement (e.g., foraging) 

• Animals adapt behaviourally to environmental feedback 

SUPERSTITIOUS BEHAVIOURS

• Reflecting apparent belief that things they do cause the reward (when there is no real causation) 

• Random reinforcement can shape behaviour 

• Even if there is no true association between behaviour and outcome, we expect and try to find links.  

• Self-perpetuating: increased display of what was reinforced before -> increased chance of being rewarded again 

• Ex. Athletes' warm-up rituals, lucky clothes 

ANIMAL TRAINING TECHNQIUES

Shaping 

• Reinforcing behaviour resembling target behaviour 

Baiting  

• Using food to bait animal into target behaviour 

Mimicking 

• Using reinforcement for animal to mimic target behaviour 

Sculpting 

• Moving and sculpting animal to perform target behaviour 

Instruction (language) 

• Using words to entice target behaviour 

CHAINING

• Many behaviours are made of smaller behaviours 

• Acquiring complex behaviour is easier if learned in chunks 

• It is often best to start with the last behaviour in the chain 

  • Called backward chaining 

  • The participant starts closer to the end goal 

REINFORCERS AND PUNISHERS

Reinforcer = increases behaviour 

Punisher = decreases behaviour  

Positive = the animal/person receives something (add) 

Negative = the animal/person loses something (subtract) 

POSITIVE REINFORCEMENT

add something to increase a behaviour 

• Ex. Get a treat when doing something good  

NEGATIVE REINFORCEMENT

removes something to increase a behaviour 

• Ex. Give night off from homework after good marks 

POSITIVE PUNISHMENT

add something to decrease a behaviour 

• Ex. Anti-barking collar on a dog when doing something bad 

NEGATIVE PUNISHMENT

removing something to decrease a behaviour 

• Ex. Lose your licence after speeding 

BRIDGING

• Combining two types of conditioning 

• Using a stimulus (CS) that has an acquired values via Pavlovian conditioning, as a positive reinforcer in operant conditioning 

• In animal training, it is useful to teach an association between a stimulus that can be delivered immediately, and a subsequent reward that can't be delivered immediately 

  • Saying 'good' 

  • Whistle 

  • Clicker 

• It comes to signal arrival of the reward – effectively bridges the time between the behaviour and primary reinforcement 

CATEGORISATION PROBLEMS

• Some examples are hard to categorise between +/- reinforce/punishment 

• Directions are still useful for understanding how and why behaviours change over time 

CONTINUOUS

Continuous (CRF) = every response 

 

PARTIAL

Partial (PRF) = only some responses 

RATIO

Delivered based on the number of times the subject performs the behaviour (frequency). 

INTERVAL

Delivered based on the amount of time that has passed.  

FIXED

The ratio or interval required is the same every time, it is consistent and predictable.  

VARIABLE

The ratio or interval is indeterminant, it varies each time and is less predictable.  

FIXED RATIO

Based on a definite number of responses.

Every nth action (ex. Every 10^th coffee is free) 

VARIABLE RATIO

Based on an indeterminate number of responses.

On average, every nth action (ex., gambling) 

FIXED INTERVAL

Based on a definite period of time.

First behaviour after n seconds (ex. Pocket money each week if clean room) 

VARIABLE INTERVAL

Based on an indeterminate period of time.

On average, the first behaviour after n seconds (ex., checking for new messages) 

A child is allowed to go outside to play with friends as long as she checks in with her mother regularly. Her mother praises her every second time she checks in.  

Fixed ratio

A pop quiz has to be completed in the lecture every three weeks.  

Fixed interval

You have a chance of winning money on the pokies each time you press the button.  

variable ratio

A factory worker is paid for each piece (assembling a certain number of units to receive money). 

fixed ratio

Fly-fishing involves frequent casting and reeling back, what schedule is a fly-fisher on? 

Variable ratio

A salesman is paid on commission for every 10^th sale.  

fixed ratio

An executive's contract specifies salary increases every 6 months.  

fixed interval

A cleaner takes a break after each level of the building is cleaned.  

fixed ratio

REINFORCEMENT SCHEDULES AND RESPONSE RATE

• Ratio more effective than interval 

  • You doing behaviour brings reward 

• Variable more effective than fixed 

  • Unpredictability  

• Post-reinforcement pause 

  • In fixed schedules 

  • Demotivation as gaps between rewards 

• Variable ratio schedule most resistance to extinction 

  • Teaches persistence 

  • Ex. Gambling 

CONTINUOUS VS PARTIAL

• Continuous reinforcement is more effective for acquiring a new behaviour 

• Partial reinforcement is more resistant to extinction 

PROBLEMS WITH PUNISHMENT

• Reinforcement is more effective than punishment 

Why? 

• Punishment isn't as permanent  

• Punishment reduces trust / increases aggression 

• Tells you what not to do, but doesn't show what you should do instead 

WHEN IS PUNISHMENT EFFECTIVE?

• Restricts escape from bad behaviour 

• Greater intensity = greater reduction in behaviour 

• Must have a continuous schedule 

• No delay in punishment 

• Must be delivered over short period of time 

• Can't have subsequent reinforcement 

• Reinforcing incompatibility  

• Watch out for side effects  

REWARD VARIABLES

Other variables apart from schedule that affect conditioning: 

Drive  

• How much the animal wants the reinforcer 

• Hungry vs not-hungry  

Size  

• Animals learn faster if they get more food pellets 

• But... diminishing returns 

Delay  

• Reinforced between when no delay 

• Temptation 

  • Immediate reinforcement but delayed punishment 

  • It can be hard to act in consideration of the delayed punishment 

LAW OF DIMINISHING RETURNS

The effect of size is much stronger when you start with smaller sizes than initially starting off at a large size. 

THE THREE TERM CONTINGENCY

1. The discriminative stimulus  

• What sets the occasion 

2. The operant response 

• The behaviour 

3. The outcome that follows 

• Reinforced/punished consequence 

THE DISCRIMINATIVE STIMULUS

The discriminative stimulus serves to signal the occasion when a particular behaviour will be reinforced/punished.  

• Learning to discriminate the stimulus is key to operant conditioning 

STIMULUS CONTROL - GENERALISATION

• When a response is reinforced in the presence of one stimulus, there is a general tendency to respond in the presence of a new stimulus that has similar physical properties or has been associated with the stimulus 

• Loose degree of stimulus control 

STIMULUS CONTROL - DISCRIMINATION

• Degree to which different stimuli signal the occasion for a particular response 

• Precise degree of stimulus control 

• Taught using discrimination training procedures such as different reinforcement 

Amy drove 120km/ph in a 100 zone every day until she received a speed ticket and fine of $500. 

positive punishment

A person with a heroin addiction begins to feel withdrawal symptoms and injects another dose to rid the unpleasant feeling.  

negative reinforcement

Rachel's lecturer compliments her writing ability and she decides to take other subjects in creative writing.  

Positive punishment

Geoff is kicked of the swimming team for binge drinking.  

negative punishment

Fiona buys her son a lolly so he stops his temper tantrum and it works.  

Fiona = negative reinforcement 

Son = positive reinforcement.  

Melonie constantly complains about her lecturer, and her students are sick of hearing it and no longer provide sympathy.  

negative punishment

Marty notices improvement in his fitness when he has to clime 6 flights of stairs every day, when his lift is fixed he still continues taking the stairs.  

positive reinforcement