Title: PSY402 Theories of Learning
1PSY402Theories of Learning
- Chapter 6, Traditional Theories
2Two Theoretical Approaches
- S-R associative theorists -- inflexible view of
behavior. - Mechanistic
- Stimulus acquires ability to elicit response
through associations formed. - Cognitive theorists flexible view.
- Mentalistic
- Learning involves recognition and understanding
of environment.
3Hulls Drive Theory
- Drive motivates behavior and drive reduction is
responsible for the S-R associative learning. - Drive an intense internal force.
- Behavior is the combined influence of several
factors, which can be expressed mathematically.
4Hulls Factors
- Excitatory potential (expectation) SER
likelihood that an event will occur. - Drive (D)
- Incentive motivation for reward (K)
- Habit strength (H) strength of the S-R
association (experience). - Inhibition also due to experience.
5Sources of Drives
- Unconditioned
- Physiological deprivation, metabolic imbalance.
- Intense environmental events with survival
consequences. - Pleasurable stimuli (such as saccharin) even
without nutritional value. - Acquired Pavlovian conditioned cues to
unconditioned drives.
6Habit Strength
- SUR an unconditioned or innate habit strength.
- SHR habit strength acquired through prior
learning experiences. - If a response reduces a drive state, habit
strength increases. - Drive reduction strengthens the S-R bond until
behavior becomes habitual.
7Inhibition
- Reactive inhibition -- if a drive persists then
all behavior is temporarily inhibited. - Conditioned inhibition continued failure to
reduce drive resulting in a permanent decrease in
behavior. - The second strongest response in the habit
hierarchy will be performed instead.
8Incentive Motivation
- Hull initially assumed that only drive reduction
influences the S-R bond. - Crespi showed that reward magnitude affects
responding. - If reward only influenced learning, the change
should be more gradual. - Hull proposed that reward also influences
motivation by increasing arousal.
9Importance of Hulls Theory
- THE dominant theory in the 1930s-1960s.
- Correct in many respects
- Intense arousal can motivate behavior.
- Environmental stimuli can develop the ability to
produce arousal, motivating behavior. - Value of the reward influences the intensity of
behavior.
10Problems With Hulls Theory
- You can get increases in behavior without drive
reduction - Olds Milner, direct brain stimulation
- Sensory deprivation motivates behavior to obtain
stimulation (Harlow). - Hulls theory does not explain how secondary
rewards can acquire the ability to increase
behavior.
11Drive-Induction Theory
- Sheffield -- drive-induction not reduction
strengthens behavior. - Rewards produce excitement or arousal which
motivates responding. - When secondary rewards are associated with
primary rewards they elicit the same arousal. - Also explains Harlows findings.
12Guthries Contiguity Theory
- Guthrie rejected the necessity of reward.
- Contiguity is enough to establish an S-R
association. - A response that occurs when a stimulus is present
will automatically become associated with it. - Learning is entirely governed by co-occurrences
contiguity in time.
13Impact of Reward
- According to Guthrie, reward is important, but it
does not strengthen the S-R association. - The effect of reward is to change the stimulus
context present prior to reward. - New actions are conditioned to this revised
stimulus context. - Reward prevents further conditioning of the
undesired behavior.
14Guthries View of Punishment
- Punishment is a stimulus that can either be
escaped or avoided. - If a response terminates punishment, it will
replace the punished behavior next time that
context occurs. - Punishment works only if the response elicited by
the punishment is incompatible with the punished
behavior.
15Importance of Practice
- According to Guthrie, learning occurs in a single
trial. - The strength of the S-R bond does not slowly
increase with experience. - Performance increases because subjects must learn
which stimuli are consistently present. - Over time, many different stimuli become
associated with a response.
16Criticisms of Contiguity Theory
- Guthrie conducted few studies to support his
theory. - Accurate parts
- Punishment can intensify inappropriate behavior
when it elicits a response compatible with the
punished response. - Contiguity is essential to prevent conditioning
of competing associations. - Not all environmental cues are noticed.
17Impact of Reward
- Guthries view of reward has been disproved.
- If what happens after a response is not
rewarding, an S-R association is not formed, even
if the stimulus changes. - Noble reward size predicts response better than
recency or frequency (contiguity measures).
18Single-Trial Learning
- All-or-nothing (single-trial) learning has been
difficult to demonstrate. - Voeks found single-trial learning of an
eye-blink response in humans. - Other studies report gradual learning.
- Spence proposed a threshold explanation of
single-trial learning using incremental learning
theory.
19Skinner
- Emphasized the importance of environment
(reinforcers contingencies). - Validation of hypothetical constructs interferes
with analysis of the variables controlling
behavior. - Anti-theory
20Spences Acquired Motives
- Spence was a colleague of Hull.
- Spence elaborated the idea that reward size
matters (K in Hulls theory). - It isnt enough to say that reward size matters
how specifically does it affect behavior? - Spence proposed a mechanism.
21Goal Responses
- Reward elicits an unconditioned goal response RG.
- This response produces an internal stimulus state
SG that motivates consummatory behavior. - Reward value determines the size of the goal
response RG.
22Anticipatory Goal Responses
- Cues become associated with reward through
classical conditioning. - These produce an anticipatory goal response rG.
- Cues lead to internal stimulus changes sG that
motivate behavior. - Thus Pavlovian conditioning motivates approach
behaviors.
23Amsels Frustration Theory
- Amsel applied Spences theory to avoidance of
aversive events - Frustration motivates avoidance.
- Frustration suppresses approach.
- Nonreward produces unconditioned frustration
response RF. - The stimulus associated with it SF motivates
escape behavior.
24Anticipatory Frustration Response
- As with goal states, classical conditioning
results in anticipatory frustration response rF. - The conditioned stimuli associated with them sF
motivate avoidance of a frustrating situation. - Example car that wont start.
- SF motivates leaving the car, sF motivates
selling it.
25Mowrers Two-Factor Theory
- Mowrer proposed a drive-based two-factor theory
to avoid explaining avoidance using cognitive
(mentalistic) concepts. - Avoidance involves two stages
- Fear is classically conditioned to the
environmental conditions preceding an aversive
event. - Cues evoke fear -- an instrumental response
occurs to terminate the fear.
26Mowrers View (Cont.)
- We are not actually avoiding an event but
escaping from a feared object (environmental
cue). - Millers white/black chamber rats escaped the
feared white chamber, not avoided an anticipated
shock. - Fear reduction rewards the escape behavior.
27Criticisms of Two-Factory Theory
- Avoidance behavior is extremely resistant to
extinction. - Should extinguish with exposure to CS without
UCS, but does not. - Levis Boyd found that animals do not get
sufficient exposure duration because their
behavior prevents it. - Avoidance persists if long latency cues exist
closer to the aversive event.
28Is Fear Really Present?
- When avoidance behavior is well-learned the
animals dont seem to be afraid. - An avoidance CS does not suppress operant
responding (no fear). - However, this could mean that the animals hunger
is stronger than the fear. - Strong fear (drive strength) is not needed if
habit strength is large.
29Avoidance without a CS
- Sidman avoidance task an avoidance response
delays an aversive event for a period of time. - There is no external cue to when the aversive
event will occur just duration. Temporal
conditioning. - How do animals learn to avoid shock without any
external cues for the classical conditioning of
fear?
30Kamins Findings
- Avoidance of the UCS, not just termination of the
CS (and the fear) matters in avoidance learning. - Four conditions
- Response ends CS and prevents UCS.
- Reponse ends CS but doesnt stop UCS.
- Response prevents UCS but CS stays.
- CS and UCS, response does nothing (control
condition).
31DAmatos Acquired Motive View
- DAmato proposed that both pain and relief
motivate avoidance. - Anticipatory pain relief responses.
- Shock elicits unconditioned pain response RP and
stimulus SP motivates escape. - Classically conditioned cues sP elicit
anticipatory pain response rP that motivates
escape from the CS.
32Anticipatory Relief Response
- Termination of the UCS produces an unconditioned
relief response RR with stimulus consequences SR. - Conditioned cues elicit an anticipatory relief
response rR with stimulus consequences sR. - Example dog bite elicits pain response, sight of
dog elicits anticipatory pain, house elicits
relief
33A Discriminative Cue is Needed
- During trace conditioning no cue is present when
UCS occurs and no avoidance learning occurs. - A second cue presented during avoidance behavior
slowly acquires rR-sR conditioning. - Similarly, in a Sidman task, cues predict relief
-- associated with avoidance behavior, not the
UCS.
34How is rG Measured?
- Anticipatory goal responses were initially
measured as peripheral nervous system (ANS)
response. - No consistent relationship between such measures
and behavior could be found. - Now, Rescorla Solomon propose that these
anticipatory states are due to CNS activity
(brain states).