Task 6 - instrumental conditioning Flashcards
Instrumental conditioning
-form of associative learning where a response is learned to obtain/avoid certain consequences
Thorndike’s puzzle box
- hungry animal is trapped in a box and can escape by performing a sequence of actions
- animal learns over trials and escapes in less time
- discrete trials
Skinner box
- animal is put in an apparatus and can respond as often as it chooses
- reinforcement/punishment is delivered automatically
- > example: press lever to obtain food
- free - operant paradigm
Free - operant paradigm
- operant conditioning
- animal can operate the experimental apparatus freely
- responding to obtain reinforcement/ avoid punishment when it chooses
discrete trials
-experimenter defines beginning and end points
Primary reinforcers
- food
- sleep
- sex
Drive reduction theory
-all organisms have a need to reduce drive to obtain primary reinforcers
Secondary reinforcers
- no value on its own put paired with primary reinforcers or make them available
- example: money
Fixe ratio schedule
- fixes number of response must be made to deliver a reinforcer
- > leads to steady rate of responses with postreinforcement pauses
- > higher nr of fixed responses, longer pause
Fixed - interval schedule
- the next reinforcer only becomes available after a fixed interval
- > leads to increased responses around the time before a new reinforcer becomes available
Variable - ratio schedule
- reinforcer follows on average a nr of responses
- > steady, high rate of responses without pauses
Variable - interval schedule
- next reinforcer becomes available after a average time intervals
- leads to steady moderate response rate
Habit slip , Protestant ethic effect
-sometimes Sd-> R association is so strong that Sd evokes R automatically, no matter what other options are available
Shaping
- instead of waiting with reward until an animal is showing desired behavior
- > successive approximations will be rewarded
Chaning
- organisms are gradually trained to execute complicated sequences of discrete responses
- also backward chaning
Negative contrast effect
-acceptable reinforcer elicits less responding if preferred reinforcer is expected
Example:
- sweetened water will elicit slightly stronger response from babies than plain water
- but if baby first gets sweetened water and then is switched to plain the difference increases greatly
Factors that determine how effective punishment will be (4)
1) punishment leads to more variable behavior
2) discriminative stimuli for punishment can encourage cheating
3) concurrent reinforcement cab undermine punishment
4) initial intensity matters
Concurrent reinforcement schedule
-organism can make any of several possible responses
Matching law of choice behavior
- rate of responding to alternatives equals rate of reinforcements available for each alternative
- > If an option gives more reinforcers, it will be chosen more frequently
Premack principle
if high-probability behaviors (more desirable behaviors) are made contingent upon lower-probability behaviors (less desirable behaviors), then the lower-probability behaviors are more likely to occur
-response deprivation theory: making something reinforcing just be simply restricting it
Basal ganglia
- nucleus accumbens
- dorsal striatum (caudate nucleus, putamen)
Dorsal striatum
- necessary for learning Sd -> R associations
- links between sensory cortex and motor cortex -> so that stimulus can evoke appropriate motor responses
Lesions basal ganglia
-deficits in ability to associate a discriminative stimulus with a correct response
Orbitofrontal cortex
- underside of front of brain
- represents predicted outcomes -> contributes to goal-directed behavior
- input: form sensory modalities
- output: to striatum -> helps determine which motor responses are executed
hedonic value
-subjective ‘goodness’ or value of a reinforcer -> linking, endogenous opioids
Motivational value
- degree to which one is willing to work to obtain access to that stimulus
- wanting
- dopamine
Ventral tegmental area (VTA)
- in midbrain
- contains dopamine-producing neurons which project to frontal cortex and other brain areas
- > WANTING
How the brain signals wanting - vta
-dopamine is produced in VTA -> projects to PFC and substantia Nigeria pars compacta (SNC) (part of basal ganglia)
Incentive salience hypothesis
- dopamine helps provide organism with motivation to work for reinforcement
- enhances wanting
Evidence: dopamine levels are highest just before reinforcements are delivered, not when they are actually delivered
How the brains signals liking - endogenous opioid
- any of a Group of naturally occurring neurotransmitter like substances
- help signal hedonic value of reinforcers in the brain
- > lessening normal perception of pain
- > feelings of euphoria
Punishment signaling in the brain - insular cortex
- locate ding old between pariatal and temporal lobe
- important for conscious awareness of own bodies and emotional states
- plays role in signaling the aversive value of stimuli
- > degree of activation appears proportional to magnitude of punisher
Drug addiction
-
dopamine pathway
- VTA (brain stem) -> nucleus accumbens (basal ganglia) -> dorsal striatum (basal ganglia)
