LEARNING
(Sereno)
Overview
I.
II.
III.
IV.
V.
VI.
What is Learning?
Classical Conditioning
Operant Conditioning
Cognitive Processes in Learning
Evolutionary considerations
Review and Perspective
I. What is Learning?
Historical perspective
Behaviorism (1900-1960)
JB Watson & BF Skinner
nurture, not nature
some definitions of learning:
• the process through which experience modifies pre-existing
behavior and understanding
• relatively persistent change in behavior as a result of experience
• an individual’s adaptation to environmental events
Habituation - simplest form of learning
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II. Classical Conditioning
Conditioning
UCS, UCR, CS, CR
extinction, reconditioning, spontaneous recovery
Relevant factors:
stimulus generalization / stimulus discrimination
timing
predictability
signal strength
attention
Applications
learned immune responses, phobias, predator control
III. Operant (Instrumental) Conditioning
Learning process by which the consequences of a response affects the likelihood
that the response will occur in the future
Thorndike: Instrumental Conditioning
puzzle boxes
learning by trial and error
law of effect the behavior of an organism is controlled by the
effects it produces
Skinner: Operant Conditioning
Skinner boxes
basic components of operant conditioning
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Basic Components of Operant Conditioning
operant = any behavioral act that has some effect on the environment
discriminative stimulus = stimulus that signals whether reinforcement is
available if a certain response is made
schedules of partial reinforcers
reward only some of the responses; overall, leads to better learning
ratio = reinforcement after certain # of responses
interval = reinforcement after certain # of seconds
fixed = reinforcement after x amount
variable = reinforcement after x amount, on average
schedule type
fixed ratio
variable ratio
fixed interval
variable interval
example: reinforce after every...
5th response
5th response, on average
20 seconds
20 seconds, on average
reinforcement vs. punishment
reinforcement = any process that increases the likelihood that a
particular response will occur
punishment = any process that decreases the likelihood that a
particular response will occur
positive = stimulus is presented
negative = stimulus is removed
Response Rate
Increases
Decreases
Response causes Presented
+ reinforce
+ punish
stimulus to be
Removed
– reinforce
– punish
shaping = successively closer approximations to the desired response
reinforced until the response finally occurs
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IV. Cognitive Processes in Learning
Cognitive views of learning (Tolman)
Latent learning & Cognitive maps (Tolman)
Insight (Kohler)
Observational learning (Bandura)
Learning language (Chomsky)
V. Evolutionary Considerations
Misbehavior of animals - “instinctual drift”
animal’s behavior drifts towards the response it is biologically
predisposed to perform
Food aversions (Garcia)
1-trial learning
biologically adaptive behavior
Imprinting (Konrad Lorenz)
species-specific learned attachment
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