Lecture 20 - Learning 2 Flashcards
(18 cards)
What is acquisition (and its curve)?
The initial increase in responding to a CS when it is paired with a US
Learning curve = reaches a plateau because learning/response is then constant
What is extinction (and its application to exposure therapy)?
The weakening of conditioned responding if the CS is subsequently presented without the US
Exposure therapy = part of CBT, presenting client with stimulus which is resulting in maladaptive behaviour
What is spontaneous recovery?
An increase in an extinguished conditioned response due to the passage of time
What is generalisation?
If learning was restricted to only the stimulus that was trained it wouldn’t be very useful
Training:
Four groups of pigeons had different-coloured key lights paired with food (bird seed):
530 nm, 550 nm, 580 nm, or 600 nm
Conditioned response – pecking the key light
Test: presented with lots of different coloured key lights
Food not delivered
Peak of conditioned response corresponded with wavelength of light reinforced
Conditioned response also elicited for lights not tested with
When conditioning is absent, animal has discriminated between training cue and new cue
Blough (1975) = some neurons conditioned during training activated (progressive weakening of conditioned responding), when no neurons conditioned during training, discrimination occurs
What can be said about biologically significant events (USs) in classical conditioning?
In classical conditioning, biologically significant events (USs) are delivered irrespective of the animal’s behaviour
What is Thorndike’s puzzle box and the law of effect?
Thorndike (1898) – at first cats would take 60-120s to escape (after a dozen trials = 20s)
The Law of Effect = “of several responses made to the same situation, those which are accompanied, or closely followed by satisfaction to the animal will, other things being equal, be more firmly connected to the situation” – formation of connection between stimulus (situation) and a response
Thorndike’s analysis of learning is that connections (or associations) are formed between a stimulus and a response (S-R)
Reinforcement merely strengthens the S-R association
What are some features of instrumental conditioning?
Instrumental lever-press responding in a Skinner box
Continuous reinforcement, ratio schedule and interval schedule
What is continuous reinforcement?
Reward is delivered every time the animal makes a response
What is ratio schedule?
Reward is delivered after a certain number of responses are made – fixed or variable
What is interval schedule?
Reward is delivered after the first response is made after a certain interval is passed – fixed or variable
What is instrumental conditioning?
Widespread – all manner of species can be trained to jump (e.g. dogs) or swim (e.g. goldfish) through hoops for reward
Sometimes hard to get started. If the animal doesn’t respond then it will never encounter reward – use “shaping”. Successive approximations to the desired response is reinforced
What is the role of contingency in superstitious behaviour in people and pigeons?
Why do people and animals not perform all sorts of strange responses given the availability of reward? – we do superstitions
B. F. Skinner = superstition in the pigeon
Although superstitions are common, they do not dominate our behaviour and life
Press lever to get water – got water every time it pressed lever at first
Chance of it getting water decreased – pressed lever very frequently
Gaining water in the absence of responding interfered with conditioning
People will work, all month, for a salary. However, if the salary is paid irrespective of effort, there is little justification for turning up for work
What are associations?
Classical conditioning = CS -> UCS
Instrumental conditioning = stimulus -> response
Why this conservative approach to learning?
Physiology – brains are mostly made up of connections between neurons (between 100 billion and 100 trillion synapses)
Occam’s Razor – other things being equal the simplest explanation is best
Is all learning stimulus-response learning?
What about the items of association (the things at the ends of the connection?)
Thorndike’s Law of Effect: of several responses made to the same situation, those which are accompanied, or closely followed by satisfaction to the animal will, other things being equal, be more firmly connected to the situation
So, a rat pressing a level for the umpteenth time has no knowledge that its action is followed food, and this, would be entirely surprised by its delivery (yes and no)
Adams (1982) - 2 groups, 2 stages of training
Stage 1 = press lever, get sugar pellet (100 times)
Stage 2 = reinforcer devaluation – got sugar pellets with no work but was made to feel ill once finished them all (devalue status of reinforcer)
Control group = sugar pellet and illness separate in time
According to Thorndike, rat will just press lever (doesn’t understand consequences)
Experimental group made fewer responses
What happens when the rats went from pressing the lever 100 times to 500 times in Adam’s (1982) experiment?
500 presses - behaviour transitions from being a goal directed action to a stimulus-response habit (experimental group pressed lever – result Thorndike expected)
What did Adam’s (1982) experiment show about what is influencing behaviour?
Adams’ experiment implies that something that is not present is influencing behaviour
Conditioning results in a representation, or image, being activated
Can a representation or an image of something not be present also be conditioned?
Holland
Stage 1 = tone-food 1, light-food 2
Stage 2 = tone -> illness
Test = food 1 vs food 2
At test, rats had opportunity to choose between food 1 and food 2
At stage 2, representation of food 1 elicited by tone
Chose food 2
Representations of things not actually present engage with things are present
Overall summary of learning
Learning is demonstrable across the animal (and non-animal?) kingdom
Habituation, classical conditioning and instrumental conditioning are 3 dominant fields of research
Research into these topics has revealed:
Insights into the cognitive abilities of animals
Applications to human behaviour, therapy and even rescue
The psychological mechanism proposed for learning = associative learning
The future? Research to gain a better understanding of the conditions of learning. When does it happen? When doesn’t it happen
