Biological 4: Learning and motivation Flashcards
(39 cards)
What is homeostasis and how does it affect behaviour?
- The body strives to main a consistent environment.
- When the body is challenged by an unavoidable loss of a regulated variable (such as energy, water, temperature etc.) there is an effect on motivation that leads to a change in behaviour.
How can homeostasis explain why it is hard to lose weight?
- Restriction of food leads to reduction in metabolic rate. (metabolism starts to slow - body wants to conserve fat)
- This limits the extent of weight loss.
Which brain systems control hunger?
- Different regions of the hypothalamus have different roles in feeding behaviour.
- Lesions of the ventromedial hypothalamus result in overeating (hyperphagia) – necessary for satiety.
- Lesions of the lateral hypothalamus resulted in weight loss (aphagia) – necessary for hunger.
Schepers and Bouton (2017) trained rats that when they were sated and pressed a lever, food would be given (association), however when they were hungry and pressed a lever, no food would be given (extinction). In the test phase, did rats press the lever more when they were sated or when they were hungry?
If behaviour is driven purely by biological needs - hungry animals should press the lever more than sated ones
Surprisingly, in the test phase, rats pressed the lever more when sated than when they were hungry.
Shows that not just the current motivational state drives behaviour - learning also does.
In this case it is context-dependent learning - rat realises that when they feel full, the outcome will happen, when they are hungry it will not, so they get food to store for when they are hungry.
What is Hull’s drive-reduction theory of learning and motivation?
Drive – the motivational state activated by a biological need
Habit - learning
Reinforcers (things that satisfy a need) reduce drive
Behavioural strength = Drive x Habit
Determines the amount of behaviour shown
e.g. amount of searching of the kitchen cupboards or rat pressing lever to get food
If either drive or habit equal zero what would happen to behaviour?
There would be none
No biological need or no learnt behaviour = no behaviour
e.g. in a new place, feeling hungry and do not know where to get food - no habit so do not have the same motivation to get food - no behaviour
e.g. If an animal was hungry (high Drive) but hadn’t learnt the correct behaviour (zero Habit) then there would be no behaviour
What predicted lever pressing behaviour in rats being harder to extinguish?
The more the behaviour had previously been reinforced (Habit, learning) and the greater the state of deprivations (Drive, motivation)
Takes longer to stop pressing lever when more hungry
The more motivated (hungry) = more behaviour
More learnt the behaviour is = more behaviour
Matches Hull’s theory
Does Hull believe that state during training (hungry or not hungry) influences whether behaviour to get food is learned?
No
Balleine (1992) tested rat’s learning of food obtaining behaviours.
Rats learned the lever press behaviour for food while hungry or while sated
On test, rats were either hungry or sated
Did motivational drive during learning of behaviour make a difference?
Yes
Animals trained when full:
No difference between behaviours on test regardless of whether they were hungry or full
Animals trained when hungry:
Much more behaviours on test for hungry rat vs full rat
Why does motivational drive during learning of a behaviour matter?
Incentive learning - animals need to opportunity to learn that the reinforcer is ‘good’
The reinforcer needs to be experienced under the correct motivational state for it to effectively strengthen subsequent behaviour
How did Fitzsimons and Le Magnen (1969) show that anticipation of need motivates behaviours in rats?
Rats given a high protein diet need to drink a lot.
When rats on a low protein diet were switched to a high protein diet they initially drank lots after meals.
Eventually, the rats increased water intake before meals
Drinking was done in anticipation of, rather than response to thirst
Collier and Johnson (1997) investigate how optimising time and effort motivates learning behaviours to obtain food.
As effort to obtain food increases, what happens to meal size and meal frequency?
Meal size increases, meal frequency decreases
Overall intake stays consistent
Behaviour is structured in anticipation of needs and reduction of expenditure of effort
Birch (1991) - preschool children either played in a room with snacks available (A) or no snacks available (B).
Pre-test - they were allowed to eat ice-cream until full
Test - both groups were allowed to play with snacks available
What was the latency before children went for the snacks in each group?
Children in room A went for snacks much quicker than children in room B
These children learned to associate the room with food, so were quicker to eat
Cues in the environment become signals to eat, drink etc. By forming associations between cues and reinforcers such as foods a state of depletion can be successfully avoided
i.e. avoid a future need to eat by learning to eat in areas where we know food is available
How does cue potentiated feeding contrast with Hull’s drive-reduction theory?
Cues associated with food lead to overeating when sated (full).
Learning can lead to feeding, even when drive is 0
Learning can lead to feeding in the absence of drive
What are the three stages of Pavlovian to Instrumental transfer?
Stage 1 - Pavlovian.
Different auditory cues paired with different outcomes
Learn distinct sounds paired with specific foods
- No response needed
- 3 sounds paired with 3 types of food
Stage 2 – Instrumental
Different actions are paired with the same different outcomes
Different levers lead to different food rewards - Left and right levers for two types of food
- Behaviour to get an outcome
Stage 3 – PIT
Can press the levers/do the action trained in stage 2
Cues from stage 1 played to see how effects behaviour
One lever available
Play cues
How does tone combined with lever determine behaviour?
What are general and specific PIT?
General PIT - If you play sound associated with food in an environment where animal can do behaviour to get food, that behaviour will be increased
- Happens for any of the cues to food
- Sound is the one associated with a food that is not associated with a particular lever (third food from stage 1)
(If sound is associated with food that involved pressing a particular lever, and that lever is not present, then this leads to behavioural inhibition)
Specific PIT - If you play same sound and lever that led to same reward in both phases
- Enhanced behaviour
Can enhance behaviour by having cues that signal rewards
- another drive for behaviour
e.g. seeing a food advert for Nando’s may make you want to eat food generally (general PIT), or may make you specifically want to go to Nando’s (specific PIT)
How is the negative contrast effect shown with sucrose solution in rats?
Experienced something really good, moved to a worse thing, that thing is going to feel even worse than if you had that thing to begin with
Rats shifted from a 32% sucrose solution to a 4% solution drink less than rats that have only had access to the 4% solution
Negative contrast: the previous experience with the 32% solution made the 4% solution taste less good. It was disappointing.
Previous experience affects reward value of behaviour
What measures of lick clusters can be taken?
How many groups of licks
How many licks per cluster
How does lick cluster size vs number of licks change with increasing concentrations of sucrose?
Number of licks peaks at about 8% - after this it gets too sweet
Lick cluster sizes indicate palatability
These increase linearly as sucrose concentration increases
Austen and Sanderson (2016) measured negative contrasts and palatability. In context A, mice were pre-exposed to 4% sucrose, and in context B, mice were exposed to 32% sucrose.
How did both groups react to a 4% sucrose test solution?
Negative contrast in context B, where sucrose concentration was reduced.
Mice drank it like it was less palatable than in context A (sort of like they are disappointed)
Lick cluster size decreased in context B, shows they found the second solution less palatable
What is incentive motivation? (Kenneth Spence) (Building on Hull’s theory)
Drive - motivational state driven by need
Habit – the extent of learning
K – incentive motivation (the motivating effect of the reward) driven by prior experience
If Drive, Habit or K equal zero then there will be no behaviour
The need to maintain homeostasis results in motivational states that affect behaviour. What are changes in behaviour only in response to biological needs?
- Changes in behaviour are not just in response to biological needs but are also in anticipation of needs
- These anticipatory behaviours reflect learning of signals of reward and the incentive value of rewards
Olds (1958) implanted rats with electrodes in the hypothalamus or VTA, and were able to press a lever that provided stimulation the the area (esp VTA).
How many times did they press the lever?
Rats pressed the lever up to 700 times per hour.
They preferred lever pressing over food.
VTA drives motivating behaviour and is rewarding beyond food
What does VTA stimulation result in?
Dopamine release
Then nucleus accumbens dopaminergic neurons signal to motor cortex to repeat lever press
(signal goes through globus pallidus and thalamus)
