Chapter 7 - Instrumental Conditioning: Motivated Mechanisms Flashcards
How is instrumental conditioning behaviour achieved in the brain?
There exists a mechanism to represent the magnitude and valence of a reward
- it monitors how responses influence the delivery of reinforcement
What is neuroeconomics?
The brain is designed to maximize reinforcement (profit) while minimizing effort (cost)
- provides an explanation for choice behaviour
What brain system codes for neuroeconomics?
Dopamine in the mesocorticolimbic pathway
Describe the role dopamine plays in motivation and addition?
- Addiction is a disorder of motivation
- All drugs of abuse increase dopamine in the striatum and nucleus accumbens
- Dopamine activity increased in the striatum of monkeys when reinforcement was given
- dopamine predicts the availability of reinforcers and instigates actions to acquire it
Where is the origin of the dopamine pathway?
In the ventral tegmental area
What does activity in the amygdala indicate?
Reward magnitude and valence
- activated with pleasure and aversive stimulus
What does increased striatal activity indicate?
Approach or do not approach behaviour
- associated with craving scores in addicts
What is the orbitofrontal cortex important for?
Decision making
- executive functions like long term planning and moral functions, last decision maker
What are the lateral and medial orbitofrontal cortices associated with?
Medial OFC - activated in response to reinforcing outcomes
Lateral OFC - activated in response to aversive outcomes
- damaged OFC - outcome value not used in decision making
What two systems guide motivation?
- habit learning
2. executive function
Describe habit learning
- influenced by lower brain structures (e.g. striatum and amygdala)
- uses prediction of next available reinforcer (and errors in prediction) to guide behavior; we like something, so we go towards it
Describe the executive function system
- Controlled by the OFC
- this is why healthy adults are better decision makers than children or animals
- filters the go/no-go desire
Describe the brain activity of a heroin addict
There is less OFC activity, but more striatal than control
- indicates a lack of restraint of reward seeking behaviour
What is the first thing that motivates instrumental behaviour?
The associative structure of instrumental conditioning - how these aspects become associated with each other
- focus on individual responses and their stimulus antecedents and outcomes
What kind of approach do all of the associative structures focus on?
Molecular approach - in the moment responses
What three factors produce or contribute to instrumental responses?
- stimulus
- response
- outcome
- aka 3 term contingency
What was the first theory of why instrumental conditioning would work?
Thorndike’s Law of Effect
- the pleasant reward/outcome would cause a greater likelihood of instrumental behaviour and the opposite for an annoying response/outcome
What was the problem with the S-R learning association?
It tells us nothing about the outcome
- the reinforcer (O) serves to stamp in the S-R association
- not learning about O or S-O or R-O
- more relevant for habit learning because you aren’t thinking about the outcome
How much of human behaviour is habitual?
about 45%
What is necessary in the formation of an association?
The outcome
What is the S-O association also called?
The reward expectancy
- in certain contexts, we are more likely to get a reward (this is the same as classical conditioning)
According to Hull and Spence, what two factors motivate the instrumental response?
- S-R association
- the stimulus comes to evoke the response directly - S-O association
- response is motivated by expectancy of reward
What is the modern two-process theory?
S-O association (pavlovian learning) > conditioned, central emotional state (positive or negative based on the reinforcer) > response
According to the modern two-process theory, what is important in affecting response?
Emotions
Does expectancy of a reward produce more instrumental behaviour?
Yes
What does PIT stand for?
Pavlovian Instrumental Transfer
- test of whether Pavlovian conditioned emotions motivate instrumental behaviour
What two brain systems are active in PIT?
- amygdala
- ventral striatum
- only when CS+ was present
Does classical conditioning influence instrumental behaviour via a positive or negative emotional state (based on reinforcer valence) or do subjects acquire specific expectations of the reinforcer?
There is evidence of specific expectations
What is the R-O association?
Response-outcome association
Do animals learn that behaviours produce outcomes?
Yes
How can we test is the R-O association is occurring?
Changing the value of the reward
Describe the hierarchical S(R-O) association?
- S activates R (habitual behaviour)
- S also activates R-O association (learning to differentiate responses in different contexts)
What is the second process that motivates instrumental behaviour?
Response allocation
How is response allocation different from the associative structure of instrumental conditioning?
Because it takes a molar view
What does a molar view entail?
How performing one response limits other activities/redistributes activities
- looks at overall consequences
What is Thorndike’s definition of a reinforcer?
A stimulus that produces a satisfying or annoying state of affairs
What is Skinner’s definition of a reinforcer?
A stimulus or outcome that increases the response that caused that stimulus to become available
What is the problem with both Thorndike’s and Skinner’s definitions of a reinforcer?
They don’t help us predict what will become a reinforcer, or if something will become a reinforcer in a given situation
- they describe the relationship between a behaviour and consequence
What helps guide instrumental behaviour?
Conditioned emotional responses
What is Sheffield’s definition of a reinforcer?
Reinforcers are species specific consummatory responses
- these are not stimuli per se but the responses that we enjoy making
- ex. eating as opposed to the food itself as being the reward
What is the consummatory response theory?
- species typical consummatory behaviours are a critical feature of reinforcers
- they are involved in the completion of an instinctive behavioural sequence
- this was the first theory that proposed that reinforcers were anything other than stimuli*
What is another definition of a reinforcer?
Reinforcers are high probability responses
What is the Premack principle?
- Difference in response probability is critical for reinforcement
- any behaviour more likely to be performed will reward for a low probability event
- reinforcement occurs when the instrumental act allows access to a more preferred (or more likely) behaviour
What is the differential probability principle?
If the low probability event (L) produces a high probability event (H), then H reinforces L, but if H predicts L, H will not reinforce L
** only goes from low to high
What did Timberlake and Allison propose?
Restricting behaviour and making it contingent on something is sufficient to produce reinforcement
What is the response deprivation hypothesis?
every behaviour has a preferred level and once access to that behaviour is restricted, then we will perform another behaviour to get it back
What is the main motivation in producing instrumental behaviour?
Maintaining or reaching homeostasis
- behavioural mechanisms can support homeostasis
What is the behavioural bliss point?
Every organism has an optimal distribution of possible activities
- preferred level of activity for each activity
What is the minimum deviation point?
The minimum unpreferred behaviour in order to get the maximum amount of preferred behaviour
What is the reinforcement effect?
- happens by making contingency necessary
- increase in occurrence of instrumental response above the level of that behaviour in the absence of the response-reinforcer contingency
ex. study time increases more than it would occur normally if watching TV is contingent upon studying
What does behavioural economics outline?
How the value of the reward changes as a function of the price
- the price of something can be time dependent as well
What are the three main characteristics of elasticity?
- substitutes (ex. coke vs. pepsi)
- if a good alternative is available - independents
- switching over to an unrelated product - complements
- related items will drop at the same rate (ex. salsa and tortilla chips)
