Instrumental Conditioning II Flashcards
Whats continuous reinforcement?
- Reinforcement provided every single time after the desired behaviour is performed
- Association is easy to make - learning occurs quickly
- Extinction also occurs quickly after reinforcement is no longer provided
Whats partial reinforcement schedules?
Only reinforce the desired behaviour occasionally rather than all the time
- slower learning = more difficult to make the association between behaviour and reinforcement
- produces behaviour that’s more resistant to extinction
- particpants tempted to persist in their behvaiour in hopes that they will eventually be rewarded
Whats the to criteria we adjust to for reinforcement schedules?
Interval - we present an outcome following a response at fixed times, for example every minute
Ratio - we present an outcome whenever the animal accumulates certain number of responses
What can both interval and ratio be?
Fixed or variable
Whats fixed interval schedules?
The animal gets the outcome for responding after a fixed period of time since the last outcome was presented
- animal learns to time the interval, so responding isn’t uniform over the minute long interval
Whats variable interval schedules?
The animal gets the outcome for responding after a non-fixed period of time
- animal can’t learn to time the interval between the outcomes
= over testing, we see uniform responding regardless of the length of the interval between outcome delivery
Whats fixed ratio schedules?
The animal gets the outcome after a fixed number of responses have been performed
- a cumulative count of responses
- animals don’t respond uniformly
- they learn the number of responses required to generate the outcome
Whats variable ratio schedules?
The animal gets an outcome after a non-fixed number of responses have been performed
- animals get the outcome after making on average 3 average responses but the number varies in training.
- like variable - interval schedule, animals respond uniformly across testing
- animals cannot learn the number of responses required to generate the outcome
Describe the graph cumulative responses?
The little lines indicate delivery of outcome
Fixed ratio - animals ger the outcome after a set number of responses = which leas to responding in burst of activity
What does the line for variable ratio look like?
Longer then variable interval and has 4 lines coming out of it
What does the line of fixed ratio look like?
Staggered like steps and at each step theres a line
What does the line for variable intervals look like
Shorter then vr and has only 3 lines coming out
What does fixed interval line look like?
Banner and at each banner there is a line
What can we notice about the interval responses compared to ratio responses?
Interval responses accumulate much slower than the ratio responses
Whats the application of these to the real world?
Reinforcement schedules are used to control behaviour in real world
Companies with performance bonuses operate a fixed ratio reinforcement
- common in banking
Explain about fixed odds bettting terminals?
Fixed odds bettting machines allow users to gamble on virtual events. Most popular = roulette
Programmed with fixed odds to give certain % of winners
Machines return between 90-95% of the money being out into machine
Whats variable reinforcement schedules?
People respond uniformly and the outcome does not alter responses
Whats ratio reinforcement?
Schedule by which responses accumulate the fastest
What does reward signal in the brain
The ventral tegmental area VTA
What does the VTA do?
Contains neurons that synthesise the neurotransmitter dopamine
Population of dopamine cells is simialr to the cells in the substantial nigra, the midbrain neurons that are lost in Parkinson disease
Whats the Mesolimbic pathway?
Consist of dopamine - producing neurons that release dopamine into the cells in the nucleus’s accumbens
The major pathway by which reward is mediated by the brain
Whats the mesocortical pathway?
Consists of dopamine producing neurons that release dopamine into the cells in the prefrontal cortex (PFC)
PFC as being involved in conscious descision making and inhibition of action
Whats the reward stimuli?
• Natural rewards that increase survival and fitness of a species activate the
reward circuit
• These behaviors and stimuli include certain food (like those containing high
sugar or fat levels), social bonding, etc.,
• Most drugs of abuse also activate the reward circuit and dopamine signaling,
which plays a critical role in the formation of addictio
Whats extinction?
the gradual weakening and eventual disappearance of a learned
response when reinforcement or association no longer occurs
Whats spontaneous recovery?
• After extinction, the conditioned response may reappear temporarily if the
CS is presented again after a period of rest.
• Learning Is Not Erased: Extinction suppresses the response but does not
completely erase the original association. Re-conditioning is typically faster
than initial learning
Whats generalisation?
the tendency for a learned response to occur in the presence
of stimuli that are similar to the original stimulus
