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
