Learning - PowerPoint PPT Presentation

1 / 74
About This Presentation
Title:

Learning

Description:

... (VTA) neurons manufacture dopamine and they are under ... with its consequence Classical or Pavlovian Conditioning Ivan Pavlov 1849-1936 Russian ... – PowerPoint PPT presentation

Number of Views:100
Avg rating:3.0/5.0
Slides: 75
Provided by: Prefer524
Category:

less

Transcript and Presenter's Notes

Title: Learning


1
Learning
  • Foundation of Behaviorism
  • Promoted by John B. Watson
  • Psychology
  • should be an objective science
  • study behavior not mental processes

2
Definition of Learning
  • Learning is an adaptive1 permanent change2 in
    behavior or behavior potential3 that is produced
    as a result of prior experience4
  • 1 occasionally maladaptive such as depressed
    mental set, obsessions
  • 2 not due to fatigue, injury
  • 3 includes tendencies to respond that might not
    have been tested
  • 4 excludes maturation, disease, instinct

3
Learning
  • Can there be learning that does not result in a
    change in behavior?
  • Types of Learning
  • Habituation (simple, single stimulus)
  • Associative Learning (simple, passive, external)
  • Cognitive Learning (complex, strategic, internal)

4
Habituation
  • Simplest form of learning
  • Response to repeated stimulus declines across
    repetitions.
  • Not due to fatigue because response will reoccur
    if stimulus is changed.
  • non-associative learning as it involves only one
    stimulus.
  • Associative learning involves two stimuli
  • (one is associated with the other).

5
Association
Event 1
Event 2
  • Learning to associate two events

Sea snail associates splash with a tail shock
Seal learns to expect a snack for its show-off
behavior
6
Associative Learning
  • Classical Conditioning associating two stimuli,
    generally one acts as a signal for the other
  • Operant Conditioning associating a behavior and
    its consequences

7
Classical Conditioning
  • We learn to associate two stimuli one signals
    the other

8
Operant Conditioning
  • We learn to associate a response with its
    consequence

9
Classical or Pavlovian Conditioning
  • Ivan Pavlov
  • 1849-1936
  • Russian neurophysiologist
  • studied digestive secretions
  • invented Classical Conditioning

10
Classical Conditioning
  • Pavlovs device for recording salivation

11
Pavlovs Experiment
12
Classical Conditioning
13
Classical Conditioning
  • Unconditioned Stimulus (UCS)
  • stimulus automatically triggers a response
  • food in mouth
  • Unconditioned Response (UCR)
  • unlearned automatic response to unconditioned
    stimulus
  • you salivate when food is in your mouth
  • physiological (hard-wired) association
  • Conditioned Stimulus (CS)
  • neutral stimulus becomes associated with UCS
  • triggers (conditioned) response
  • Conditioned Response (CR)
  • Nearly the automatic response
  • But it is learned, slightly weaker (a bit less
    salivation in our example)

14
Effect of unreinforced trials (tone without food
following it)
15
Classical Conditioning
  • Acquisition
  • the initial stage of learning, during which a
    response is established and gradually
    strengthened
  • Extinction
  • diminishing a conditioned response
  • occurs when an unconditioned stimulus does not
    follow a conditioned stimulus

16
What makes a good signal
17
Classical Conditioning
  • Spontaneous recovery
  • reappearance, after a rest period, of an
    extinguished conditioned response
  • Generalization
  • tendency for stimuli similar to the conditioned
    stimulus to evoke similar responses
  • Discrimination
  • the ability to distinguish between a conditioned
    stimulus and other similar stimuli that do not
    signal an unconditioned stimulus

18
GeneralizationLittle Albert
19
Cognitive Development
  • Never hug and kiss them, never let them sit on
    your lap. If you must,
  • kiss them once on the forehead when they
    say good night. Shake
  • hands with them in the morning. Give
    them a pat on the head if they
  • have made an extraordinarily good job of
    a difficult task. Try it out. In
  • a weeks time you will find how easy it
    is to be perfectly objective with
  • your child and at the same time kindly.
    You will be utterly ashamed at
  • the mawkish, sentimental way you have
    been handling it.
  • John Watson

  • Psychological Care
  • of Infant
    and Child

20
Classical Conditioning
  • Temporal Contiguity was thought to be sufficient
    the CS simply needs to occur immediately prior
    to the UCS for conditioning to take place
  • Equipotentiality any two stimuli could be
    associated through conditioning

21
  • Reliable signal? Informative and contingent

22
Temporal Contiguity is Not Enough
  • Contingency The CS must reliably predict the
    occurrence of the UCS (Rescorla, 1966)
  • Informativeness The CS must provide new
    information for predicting the occurrence of the
    UCS

23
Informativeness Blocking
  • If an organism has already learned that one CS
    predicts the UCS, that will block the
    conditioning of a new CS if the new CS does not
    provide any additional information
  • Example Fear conditioning of a tone blocks
    conditioning of a light

24
Blocking
Training 1 Training 2 Test
-none- Tone Light, shock (CR fear) Light ? Fear
Tone, shock (CR fear) Tone Light, shock (CR fear) Light ? No Fear
25
(No Transcript)
26
Classical Conditioning
  • Goes awry
  • Normally neutral stimulus becomes signal of
    negative CR

27
Nausea Conditioning among Cancer Patients
28
Classical Conditioning Drug Tolerance Example
  • Drug Tolerance
  • Drugs have less of an effect when taken
    repeatedly (less of a high)
  • Drug users crave more of the drug despite its
    lessening effects
  • Certain drugs trigger our body to call upon its
    defenses against the effects of the drug
    (parasympathetic or shutdown system)

29
Siegel (1977, 1983)
  • Demonstrated that classical conditioning
    principles might be in effect during
    drug-injecting episodes
  • Possible reason for overdoses

30
Siegel (1977, 1983)
  • UCS ----------------------------------------------
    ? UCR
  • (drug)
    (anti-drug defenses)
  •  
  • CS ----------------------------------------------
    -? NO RESPONSE
  • (injection ritual)
    (no defenses)
  • CS UCS --------------------------------------?
    UCR
  • (injection ritual) (drug)
    (anti-drug defenses)
  • Repeated several times
  • CS -----------------------------------------------
    ? CR
  • (injection ritual)
    (anti-drug defenses)
  •  

31
Siegel (1977, 1983)
  • Familiar setting--------------------? anti-drug
    defenses
  • (usual time, place, etc) (body
    reacts)
  •  
  • New setting ----------------------------? no
    defenses
  • (place, time are different) (body doesn't
    react)
  • Same dosage becomes an overdose they get too
    high as their bodies have been fooled by the new
    procedure, no signals to start dampening down of
    response

32
Atkinson, Krank, and McCully (1982)
  • Lab rats preconditioned to tolerate large doses
    of heroin
  •  
  • Trial 1.Room 1.SalineRats okay
  • Trial 1.Room 1.Drug.Rats get high
  •  Trials 2-19 are identical to Trial 1
  •  
  • Trial 20.Room 2.SalineRats okay
  • Trial 20 Room 2.Drug..Rats die

33
Atkinson, Krank, and McCully (1982)
  • Results
  • gt50 increase in death rate in new room
  • Rats show "room-specific" tolerance
  • May explain overdoses in humans
  • Practical implications as far as detoxification
    is concerned (returning clean addict to street,
    friends)
  •  

34
(No Transcript)
35
Operant Conditioning
  • Law of Effect (Thorndike)
  • Rewarded behavior is repeated
  • Operant Conditioning
  • behavior strengthened if followed by
    reinforcement
  • behavior weakened if followed by punishment

36
Trial-and-error learning
37
A cats Behavioral Repertoire (here, for escaping
an enclosed space)
38
(No Transcript)
39
(No Transcript)
40
Operant Conditioning
  • Operant Behavior
  • voluntary behaviors
  • operates acts on environment
  • Behavior ? Consequences
  • Reinforcer
  • any event that follows behavior AND
    strengthens it

41
Operant Conditioning
  • B.F. Skinner (1904-1990)
  • Built on Thorndikes Law of Effect
  • Discovered schedules of reinforcement

42
Operant Conditioning
  • Operant Chamber (Skinner Box)
  • chamber with a bar that an animal can press to
    obtain a food reinforcer
  • Frequency of responses are recorded

43
Principles of Reinforcement
  • Primary Reinforcer
  • innate reinforcer, satisfies biological need
  • e.g., food, water, warmth
  • Secondary Reinforcer
  • conditioned reinforcer, gains its reinforcing
    power through association with primary reinforcer
  • e.g., money

44
(No Transcript)
45
Schedules of Reinforcement
  • Continuous Reinforcement
  • reinforcing the desired response each time it
    occurs
  • learning occurs rapidly
  • extinction occurs rapidly
  • Partial Reinforcement
  • reinforcing a response only part of the time
  • learning occurs slowly
  • resistance to extinction

46
Schedules of Reinforcement
47
Schedules of Reinforcement
  • Fixed Ratio (FR)
  • behavior is reinforced only after the behavior
    occurs a specified number of times
  • the faster you respond, the more rewards you get!
  • different ratios
  • very high rate of responding
  • like piecework pay

48
Schedules of Reinforcement
  • Variable Ratio (VR)
  • behavior is reinforced after an unpredictable
    number of times
  • like gambling, fishing
  • very hard to extinguish because of
    unpredictability

49
Schedules of Reinforcement
  • Fixed Interval (FI)
  • behavior is reinforced only after a specified
    time has elapsed
  • frequency of behavior increases when the time for
    reward draws near

50
Schedules of Reinforcement
  • Variable Interval (VI)
  • behavior is reinforced at unpredictable time
    intervals
  • produces slow, steady responding
  • like pop quiz!

51
Reinforcement Schedule examples
  • Buying a lottery ticket and winning vr
  • Watching seeing a shooting star vi
  • Receiving allowance Saturday for having clean
    room fi
  • Hotel maid gets 15-min break after cleaning four
    rooms fr

52
Discrimination Demo
  • 1 for getting right answer, owe 1 for wrong
  • Mother Father Friend (triangle)
  • - Son Sister Uncle

53
Shaping
  • Can leave lab once rat touches lever three times
    in 10 seconds

54
(No Transcript)
55
Shaping
  • Successive approximations to goal behavior

56
Punishment
  • An aversive event that decreases the behavior
    that it follows

57
Reinforcement Punishment
  • Positive reinforcement
  • Negative reinforcement
  • Positive punishment
  • Negative punishment

58
Operant Conditioning
Positive negative reinforcement Positive
negative punishment
59
Problems with Punishment
  • Punished behavior is not forgotten, it's merely
    suppressed
  • behavior returns when punishment removed
  • Causes increased aggression
  • Creates fear
  • That may generalize to undesirable behaviors,
    e.g., fear of school
  • Does not necessarily guide toward desired
    behavior
  • reinforcement tells you what to do
  • punishment tells you what not to do
  • Punishment teaches you mostly how to avoid it

60
Operant vs Classical Conditioning
61
(No Transcript)
62
Behaviorism cannot explain
  • Latent Learning learning without reinforcement
    (Tolman Honzig, 1930)
  • Observational Learning learning without
    behaving or being reinforced directly (Bandura,
    1977)
  • Overjustification when rewards decrease the
    frequency of behavior
  • Language Acquisition Chomskys critique
  • marked the end of behaviorism as the dominant
    paradigm of psychology

63
Latent Learning learning that occurs but is not
apparent until there is a reinforcer to
demonstrate it  Group 1 no food reward
Group 2 always food reward Group 3 food
after 10 days  
64
Behaviorism cannot explain
  • Latent Learning learning without reinforcement
    (Tolman Honzig, 1930)
  • Observational Learning learning without
    behaving or being reinforced directly (Bandura,
    1977)
  • Overjustification when rewards decrease the
    frequency of behavior
  • Language Acquisition Chomskys critique
  • marked the end of behaviorism as the dominant
    paradigm of psychology

65
Observational Learning
  • Bobo Doll study (Bandura)

66
Behaviorism cannot explain
  • Latent Learning learning without reinforcement
    (Tolman Honzig, 1930)
  • Observational Learning learning without
    behaving or being reinforced directly (Bandura,
    1977)
  • Overjustification when rewards decrease the
    frequency of behavior
  • Language Acquisition Chomskys critique
  • marked the end of behaviorism as the dominant
    paradigm of psychology

67
Language acquisition
  • Chomsky Association is insufficient to explain
    language learning. We acquire RULES of language,
    not instances
  • Evidence Over-regularization (goed)
  • Conclusion Mere associations between words
    cannot explain language
  • Behaviorism lacks
  • Symbolic Representation we have (internal)
    representations for things in the world
  • Structure we learn sets of rules for combining
    symbols (e. g., grammar), not mere associations
    between pairs of symbols
  • Lead to Cognitive paradigm in psychology

68
Is brain-behavior behavior?
  • If so, it can be conditioned just like other
    behaviors
  • Two current fields Neurotherapy and
    Brain-Computer interfaces (BCI)

69
Electrical stimulation of brains (ESB)
  • Electrical stimulation of brains of rats - James
    Olds in 1950s
  • Jacobsen and Torkildsen replicated work in
    humans
  • some epileptics stimulated themselves into
    convulsions

70
INTRA-CRANIAL SELF-STIMULATION
  • Rodent wireheads
  • 0.0005 amperes for less than a second whenever
    rat pushed lever
  • Rates of up to 10,000 bar-presses an hour
    recorded
  • Medial forebrain bundle passing through lateral
    hypothalamus and ventral tegmentum
  • An animal will self-stimulate for more than 24
    hrs continuously without rest, and will cross
    electrified grid to gain access to lever
  • Other brain centers are aversive, such as
    periaqueductal grey matter (PAG)
  • Ventral tegmental area (VTA) neurons manufacture
    dopamine and they are under continuous inhibition
    by gamma-aminobutyric acid (GABA) system, an
    important component of the final common pathway"
    of reward, implicated in addiction, mood, and
    learning.

71
Biofeedback
  • Neal E Miller trained autonomic functions
  • Rats control heartrate to get water
  • Dogs salivate to get food

72
/- together leads to organism shutdown (internal
inhibition)
  • Pavlov conditioning experiments
  • Tone for food, buzzer for shock
  • Moved them closer together in time
  • confounded dog fell asleep
  • Termed internal inhibition
  • Animal can close down own systems to avoid stress

73
Two forms of Biofeedback PNS CNS (peripheral
and central)
  • Peripheral Body (skin) temperature, GSR (skin
    conductance), muscle (EMG), heart rate
    variability, breathing, pulse

74
CNS Central Nervous System biofeedback
When you become aware of your own brain
activityyou can change it
Write a Comment
User Comments (0)
About PowerShow.com