Operant Conditioning

Hadley D’Souza

A Daily phenomenon

• One of the two most common ways of learning

new things

• Learning= acquiring new behaviours

• Operant also known Instrumental- Rewards

(reinforcements) , Punishments.

• Skinner and Thorndike.

Origin

• Burrhus Frederic Skinner (B.F. Skinner)-

regarded as Father of Operant Conditioning.

• However, his work was based on Edward

Thorndike’s ‘Law of Effect’

• Thorndike- believed- the pleasure

(reinforcement) or discomfort (punishment)

caused by a stimulus can either strengthen or

weaken a particular behaviour.

Skinner Box

Reinforcement: Positive

• Skinner placed hungry rat in box

• Rat would keep moving around searching for

food

• By chance, it would press the lever and food

would appear in the container.

• Consequently, rat learnt to press the lever

directly to obtain food

• Here the rat learns (acquires) a particular

beahviour (pressing the lever) in order to

obtain the reinforcement (food pellets)

• This is positive reinforcement: behavior

strengthened

Negative

• Skinner would subject-rat to mild electric

shock

• Rat would run around the box

• Eventually press a lever by chance

• This lever stops the current

• The rat learns to immediately go to the lever to

stop the current

• Here rat learns to engage in certain behaviour

to stop the painful stimulus.

• This is negative reinforcement.

• >Behaviour that is learnt by receiving

something pleasant- Positive Reinforcement

• >Behaviour that is learnt by removing

something unpleasant- Negative

Reinforcement.

2 more Phenomenon

• 1: escape learning: the rats learnt to

straightaway head for the lever to escape the

current.

• 2: avoidance learning: Skinner started turning

on a light before giving the current. The rats

learnt to associate the light to the current- rats

went to the lever simply at the sight of the light

to avoid the current completely.

Punishment: Positive

• Rat has learnt to press lever by reinforcement.

• But now, If rat is given a shock for pressing

the lever- rat will learn to stop doing it-

behaviour weakened.

• Giving something unpleasant to weaken the

behaviour is Punishment (positive)

Negative

• Suppose the rat is given food regularly, but not

if it presses the lever: It stops pressing lever.

• If something pleasant is taken away, it leads to

weakening of behaviour.

• Giving unpleasant stimulus- Positive

Reinforcement.

• Taking away a pleasant stimulus- Negative

Reinforcement.

Reinforcement vs. Punishment

• Anything that strengthens behaviour- reinforcement

• > positive reinforcement is where a reward is given to strengthen behaviour

• > negative reinforcement is where a painful stimulus is removed to strengthen behaviour

• Anything that weakens a behaviour- punishment

• > positive punishment is where a punishment is given to weaken behaviour.

• > negative punishment is where something pleasant is taken away to weaken behaviour.

• PR- pleasant stimulus given [more pocket

money]

• NR- unpleasant stimulus removed [seminar

topic reduced]

• Both will strengthen behaviour

• PP- Unpleasant stimulus given [extra seminar]

• NP- pleasant stimulus removed [pocket money

taken away]

• Both will weaken behaviour

Other concepts:

• Shaping: developing a behaviour using reinforcements and punishments- from simpler to more complex tasks. [ex; training a dog]

• Extinction: stopping punishments and reinforcements-> behaviour will have no reason to continue.

• Generalization: after getting used to engage in a particular behaviour in a particular situation, may engage in the same behaviour in other similar situations. [a tortured prisoner may show a fear of all people]

• Discrimination: opposite of generalization.

Here one learns that all situations may not

yield same reward/punishment as the one

which was learnt. [ex: the tortured prisoner

will learn to differentiate between his torturers

and other human beings]

Schedules of Reinforcement

• Continuous Reinforcement Schedule: Reinforcements are continuously given.

• Partial or Intermittent Schedules:

A. Ratio Schedules:here a fixed number of responses will be awarded a fixed number of reinforcements. EX: getting ‘A’ in all exams is rewarded with a new video game.

fixed ratio: a reinforcement will surely follow after a certain number of behaviours.

variable ratio: the number of times the behaviour should be performed to obtain the reinforcement varies from one reinforcement to the next.

B. Interval Schedules: Reinforcement does not

depend on the number of times behaviour has

occurred, but on a certain period of time.

EX: Monthly salary.

Fixed interval: the time gap between

reinforcements is constant.

Variable interval: the time gap between

reinforcements varies.

Implications and limitations

Like animals, humans too learn more or less in a similar way.

Based on observable behaviour, influence of environment

Did not consider insight, cognition, or genetics.

One argument- Experiments on animals cannot be generalized to humans as physiology and mental capacities are very different.

THANK YOU!

• References:• >Bauer,A., Maracich,C., ‘Skinner’s Operant

Conditioning’. Retrieved from http://www3.niu.edu/acad/psych/Millis/History/2003/conditioning.htm

• >McLeod, S. A. (2007). ‘Skinner - Operant Conditioning’. Retrieved from http://www.simplypsychology.org/operant-conditioning.html