-
Learning
- changes in behavior that results from an animal's interaction with its environment
- More precise:
- -specific to the event experienced
- -adaptive: species that adapt to learn will survive more than others
- -lasting
- -change of, modification in, or creation of, a single behavior
- -involving the nervous system
- -as a result of experience with an external event or series of events in an individuals life
- -excludes fatigue, hormonal changes, other developmental or maturational processes, injury
-
can you observe the learning process?
- no you can only see the results
- (see expression of responses as a result of learning)
-
memory
the changes in the nervous system by which information is stored during learning
-
coincidence
contingency
- coincidence: 2 events happen together by chance
- contingency: two events happen together more often than they should by chance
-
Information
predictable departures from randomness
-
Brains and info processing
- Brains are like contingency detecting and exploiting machines
- -perception is the filtering of info from randomness
- -learning is the ability to adapt responses to new contingencies (info) that are not programmed in the genes
-
What are the two main approaches to learning in non-human animals?
- Ethologists
- Comparative psychologists
-
ethologists view on learning
- function that learning plays in the animal's natural environment
- phylogenetic differences in learning abilities
- role of leaning in development
-
comparative psychologists view on learning
- elucidate mechanisms underlying learning
- general "law" of leaning
-
Categories of Learning in ethology and comparative psychology
- Non-associative learning: animal is exposed repeatedly to a single stimulus, and behavior changes
- Associative learning: animal is exposed to 2 or more stimuli that have a particular relationship to one another. Animal demonstrate associative learning if response to one stimulus is altered by exposure to the second.
- complex learning: insight, reasoning
-
Non-associative learning: habituation
- waning of a response, when a stimulus is repeated, even though the full response could still be made
- most primitive and universal form of learning
- eg a dog in a new home may be startled by the sound of a door opening, but over time this startle response slowly disappers
-
Classic example of habituation (non associative learning)
- Aplysia (marine slug)
- -given a tactile stimulus
- weak stimulus: took longer to habituate to than a strong stimulus
- (however maybe the muscles in the slow were just too exhausted to respond?)
- after a rest full recovery of response is seen
-
Dishabituation
recover of response strength due to a strong novel stimulus (i.e. increase intensity)
-
Associative Learning
and ex
- Association between one stimulus, and either another stimulus or the animals own behavior, leads to a change in behavior
- ex. pigs in a swine unit may associate feed with the sound of the feed truck, time of day, stockman's presence, and begin salivating before food actually arrives
- ex. rats in a maze may associate food with the act of entering a particular corridor, and enter that corridor repeatedly each time they run this maze
- ex cows become nervous when vet truck arrives
-
Varieties of Associative Learning
- Classical condition:
- -associations between events over which the animal has no direct control (ie feeding truck and food)
- -requires multiple exposures
- Instrumental Conditioning
- -the animal's behavior is instrumental in learning (eg choosing the correct corridor in a maze)
- -requires multiple exposures
- Passive avoidance learning (taste aversion learning)
- -eg rats can eat a novel food, become sick several hours later, and will avoid the food in the future
- -probably very different from classical and instrumental conditioning, not least because ir requires ONE exposure
-
Give a classical conditioning example
Blue Jays eat monarch butterfly's and then throws up (so don't eat again)
-
Classical Conditioning: stimulus and response for pavlovs dog experiment
- unconditional stimulus (UCS): puff of air
- unconditional response (UCR): eye blink
- neutral stimulus (NS): tone "sound"UCS and NS are presented together after repeated presentations, the animal responds to both UCS and NSNS is NOW referred to as a conditional stimulus (CS) and UCR is termed the conditional response (CR)
-
Classical Conditioning
- an Existing behavior is elicited by a new stimulus neutral stimulus
- can result in unconditioned response if paired with UCS
- long lasting
- "pavlovian learning"
-
2nd order conditioning
- the CS can act like an UCS for a new NS
- ie a flashing light (NS) can be paired with a bell (CS) and the dog will salivate to the flashing light
-
Extinction
Disrupt association between UCS and CS-present CS with no UCSRing bell without giving dog food -so prevent a stimuli without supporting it
-
Instrumental Learning
- Classical Conditioning (pavlovian learning)
- -the animal has no control over events that are changing its environment
- -it just comes to respond to one event as if it were another
- Instrumental conditioning (instrumental learning, operant conditioning, trial and error learning
- -animal can behave spontaneously, its behavior is instrumental in the learning process
- -learn from results of action
- This is occurring all the time, even when you don't want it to!
- -dog jumps up and receives social interaction
- -cat scratching furniture
-
Instrumental learning: teaching a puppy to sit
- learns more readily if response occurs spontaneously rather than forced (pushing on back end)
- food reward in hand, lift hand up, with one hand behind puppy to prevent 'backing up' and puppy naturally sits
- as puppy sits say sit and reward (reinforce) immediately (food and praise are the reinforcing stimuli - DO NOT reward non sitting
- eventually raised hand becomes visual clue for sitting; just as "SIT" becomes an auditory one
animal is active and specifically involved in process
-
B.F. Skinner
- believed that instrumental conditioning was behind most if not all complex behaviour: his point was pivotal to modern behaviorism (because almost all complex acquired behavior could in theory be explained using instrumental learning)
- Skinner referred to instrumental conditioning as operant conditioning
- -
skinner box: very simple barren enviro to study operant conditioning in pure, uncorrupted form - ie mouse has a lever which puts food in
-
Operants
- Operant- behavior that the experimenter wishes to alter the chance of being performed
- (operants ie pecking key, pressing lever, sitting)
- The animal must learn association between stimuli, responses, and consequences
- shape behavior: when animal gets close to doing what should, give rewards, only reward again if gets even closer
- with shaping, very complex sequences can be taught
-
Clicker training
- works with operant behavior
- clicker associated with positive reinforce (usually food)
- Click (CS) and treat (UCS) - the click becomes classically conditioned as a secondary reinforcer
- the click is as if it were a treat
- used to shape behavior- give a click to give the animal small rewards for each approximation
- so sound became positive on its own without food
-
Ecological constraints on learning
- Does shaping really make sense? How can animals learn in the wild if there is no-one there to shape them?
- in fact few operants in a skinner box reflect anything an animal would do in the wild
- For example:
- pigeons can be taught extremely complex tasks (such as telling Picasso from monet) if the operant is to peck a key, and the reward is food
- in fact they were even able to generalize from Picasso to other cubist painters and from monet to other impressionists
- BUT it was almost impossible to teach a pigeon to peck a key for a non-food reward such as access to a mate
-
Key definitions of reinforcement and punishment
- 1. want behavior to increase with positive reinforcement
- 2. remove already applied stimulus to reinforce behavior
- 3. stimulus presented and the behavior decreased "ie positive punishment"
- 4. stimulus already present gets taken away and behavior decreases
-
Punishment
- 'punishment' is used in common speech to mean "positive punishment"- performing behavior results in noxious stimulus, intended to prevent a behavior
- timing is critical
- Intensity: optimal level is the minimum required to suppress response which is very difficult to judge in practice
- positive punishments have side effects: unpredictable behavior, fear, suppression of all behaviors, makes learning harder if not right the first time
hard to apply appropriately because animal needs to associate behavior with punishment
-
Reinforcement schedule
- Animals work harder when reinforcements are
- a) few and far between
- b) relatively irregular and unpredictable
extinction- friend and foe
- continuous
- fixed interval
- variable interval
- fixed ratio
- variable ratio
-
KNOW
different types of reinforcement schedules
**Go into notes review chart
- continuous reinforcement (CRF)
- Fixed interval (F1)
- Variable Interval (V1)
- Fixed ratio (FR)
- Variable ratio (VR)
-
Do classical and operant conditioning offer evidence for higher mental processes in animals?
- NO: they are simply association between stimulus and response
- ability to learn per stimulus and response is not enough to infer any sort of comprehension
- goal directed trial and error
-
Examples of complex forms of learning
- thinking/prediction/mental simulation
- latent learning
- cognitive maps
- learning-set learning
- insight learning
- tool use, and tool making
-
Mental simulation
Latent Learning
- Mental simulation: is the ability to run a simulation of trial-and-error learning, and to learn from it
- -obvious advantages: less costly, quicker
- -Basis of "thinking"
- Latent Learning: Putting together 2 separate experiences that have never occurred together as if they had been instrumentally conditioned
- (so taking an event that happened in the past and using that info later on, but in diff enviro)
- -may involve mental simulation
- -again obvious biological advantages
latent learning ex: ie mouse in a maze gets shocked in a black square... later on in a new maze there is a black square and it avoids it
|
|