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The partial reinforcement extinction effect (PREE). Frode Svartdal University of Tromsø Oct. 2013. Extinction: Basics. Extinction is defined in terms of a reinforcement process Extinction contingencies The stimulus (S R or US) is discontinued The learning contingency is discontinued

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the partial reinforcement extinction effect pree
The partial reinforcement extinction effect (PREE)

Frode Svartdal

University of Tromsø

Oct. 2013

extinction basics
Extinction: Basics
  • Extinction is defined in terms of a reinforcement process
  • Extinction contingencies
    • The stimulus (SR or US) is discontinued
    • The learning contingency is discontinued
  • Extinction process
    • The conditioned response is reduced (strength, frequency, etc.)
    • Relearning, … not forgetting
extinction basics1
Extinction: Basics

Operant conditioning

Catania, 1984)

extinction basics2
Extinction: Basics

Classical conditioning

factors affecting the extinction rate
Factors affecting the extinction rate
  • In general: Fast acquisition / high rate of responding  fast extinction
  • Amount of reward
    • High  fast extinction
  • Variability
    • Stimulus
    • Response
    • Reinforcement
  • Some forms of learning do not extinguish (easily)
    • Evaluative conditioning (e.g., Diaz, Ruiz, & Beyens, 2005)

= high ext. persistence

factors affecting the extinction rate1
Factors affecting the extinction rate
  • Partial Reinforcement Extinction Effect
    • Partial (Intermittent) Reinforcement (PRF)  increased extinction response
    • Continuous Reinforcement (CRF)

 reduced extinction persistence

slide7

First demonstrations

Operant conditioning;

free operant; rats;

Skinner (1938)

Classical conditioning;

blink response; students;

Humphreys (1939)

50%

100%

slide8

Free operant

Ferster & Culbertson, 1975

slide9

EXTINCTION

Free operant

  • Compared to CRF:
  • PRF 
  • higher asymptotes
  • more persistent
  • responding under
  • extinction

PRF

CRF

slide10

Rats, maze running speed under extinction

(Weinstock, 1954)

PRF (30%)

CRF

slide11

Classical conditioning (rats): PREE

Extinction

25%

PRF response rate

LOWER than CRF

response rate

50%

100%

15%

slide13

Operant conditioning; humans;

Svartdal, 2003, Exp. 4

conclusions preliminary
Conclusions (… preliminary)
  • PREE is a very robust outcome
    • Measures & species
      • Bar pressing, rats
      • Maze running, rats
      • Pecking, pigeons
      • Blink reflex, humans, rabbits
    • Contingency
      • Operant/instrumental
        • Discrete trial
        • Free operant
      • Classical
slide15
But…
  • How general is the PREE?
    • Reversed PREE observed under some conditions
    • Generalized PREE observed under some conditions
  • Alternative methods of analysis
    • Nevin (1988): ”PREE is an artefact because of wrong method of analzing extinction performance”
  • Response unit issue
    • PREE or not dependig on how the response is defined (Mowrer & Jones, 1945!
slide16

Reversed PREE

What happens if the subject

is exposed to a mixture

of PRF and CRF contingencies?

reversed pree
Reversed PREE

Pavlik & Carlton, 1965: Rats; bar pressing, free operant

  • Gr. 1: Single contingency; CRF
  • Gr. 2: Single contingency; PRF
  • Gr. 3: Two signalled schedules alternated for the same subjects; CRF + PRF
reversed pree1
Reversed PREE

Conventional

PREE

reversed pree3
Reversed PREE

Pavlik & Carlton (1965):

  • Single reinforcement schedules (CRF vs. PRF) in between-groups experiments PREE
  • Two schedules (CRF vs. PRF) for the same subjects  Reversed PREE

Other research

  • Reversed PREE observed
  • Generalized PREE (overall increased persistence, but no difference between conditions)
  • Conventional PREE rarely if ever observed in within-subjects manipulations of CRF - PRF
pree as a generalization ecological validity
If applied to a situation with a very specific schecule for a specific behavior  PREE

Example:

Single mother – child is begging for toys only from mom

If applied to various situations with mixed contingencies  Reversed PREE

Generalized PREE

Example:

Mother and father – child begs for toys from both

PREE as a generalization: Ecological validity
free operant responding what is the response unit
Free operant responding: What is the response unit?

Mowrer & Jones,1945:

What should be counted as the response unit - single responses or the unit of responses required for reinforcement?

  • Free-operant
  • Intermittent reinforcemet, e.g., FR4
response unit
Response unit

FR4

Reinforced responses

slide25

PREE

Total responses

Reversed PREE

Total responses /

reinforcement ratio

pree alternative analyses
PREE: Alternative analyses

Nevin, 1988: Behavioral momentum

  • ”RPREE” is the rule – the response is stronger following CRF
      • in free-operant responding (but not in discrete-trial experiments)
      • following extended training
  • Extinction performance
    • Traditional measure: Number of responses
    • Nevin: Slope of the extinction curve
slide28

SHORT

LONG

Nevin, 1988

Absolutenumber

of responses

PREE

RPREE

Relative to initial

extresponse

level

pree vs rpree important variables
PREE vs. RPREE – important variables
  • Dependent measure
    • No. of responses vs. relative change
  • Type of situations
    • Free operant vs. discrete trial
  • Complexity of situation
    • One vs. more schedules (e.g., multiple schedule)
  • Design
    • Between groups vs. within subjects
pree my interests
PREE: My interests
  • Interaction PREE & Reversed PREE
  • Cognition (verbalization) related to behavioral PREE
the experimental situation
The experimental situation

”Computer responses”

presented

Left, right

Subject responses

recorded

Left, right

the experimental situation1
The experimental situation

Task

  • Complete a four-response chain of responses started by the computer
    • E.g.: Computer: L R Subject: R L
  • Instructed task: Identify and apply the functional rule(s)
    • ”Obtain as many correct answers as you can.”
  • Rules (depending on experiment)
    • ”Repeat computer sequence”
    • ”Reverse computer sequence”
  • Feedback (visual, autitory) for correct answer; nothing happens if answer is incorrect
the experimental situation2
The experimental situation

Manipulations (between

groups and/or within groups)

Rule

Reverse (typically used)

Repeat

Contingency

CRF (100%)

PRF (20-60%)

the experimental situation3
The experimental situation
  • Reward rate manipulated
    • Between groups
    • Within subjects (multiple schedule)
  • Discrete trial situation; fixed number of trials
    • 180 acquisition trials
    • 40 extinction trials
reversed conventional pree operant responding students svartdal 2000
Reversed & conventional PREE; operant responding; students; Svartdal, 2000

Reversed PREE

  • Purpose: Explore the relationship between PREE and RPREE
  • PREE vs. RPREE: Contradiction or compatible effects?
  • Method
    • Independent groups: PRF and CRF
    • Within: CRF and PRF
svartdal 2000 ctd
Svartdal, 2000 ctd.
  • Multiple schedule, alternating
  • Group 40/40
    • Half trials (signalled): 40%
    • Half trials (signalled): 40%
  • Group 80/80
    • Half trials (signalled): 80%
    • Half trials (signalled): 80%
  • Group 80/40
    • Half trials (signalled): 80%
    • Half trials (signalled): 40%

PRF

”CRF”

”CRF”+ PRF

slide39

* No. of responses: RPREE

* Relative change: No difference

80%

PREE

40%

svartdal 2000 ctd1
Svartdal, 2000 ctd.
  • Relationship between schedule components
  • Simplest assumption: Modulation between component schedules:
    • 60% + context = 60% reference
    • 60% + context = 100% reduced persistence
    • 60% + context = 20% increaced persistence
slide41

Performance of a 60% schedule depending on

other schedule = 100%, 60%, or 20%

Svartdal, 2000

slide42

Svartdal, F. (2000). Persistence during extinction: Conventional and Reversed PREE under multiple schedules.Learning and Motivation, 31, 21-40.

cognition in pree
Cognition in PREE
  • Currently: Strong cognitive arguments to interpret conditioning in terms of cognition
    • Classical conditioning: Lovibond & Shanks, 2002
    • Operant conditioning: Shanks & St John, 1994
    • Implicit learning doubted: Shanks, 2005
    • Extinction: Lovibond, 2004
  • Basic argument:

CONTINGENCY  CONSCIOUS APPREHENSION  BEHAVIORAL CHANGE

CONTINGENCY  CONSCIOUS APPREHENSION  NO BEHAVIORAL CHANGE

  • Large number of studies supporting this assumption
cognition in pree1
Cognition in PREE
  • So, since the behvioral PREE is very robust, a ”cognitive PREE” must be easy to measure
  • Basic prosedure:
    • Behavioral acquisition under 100% vs. 60% reinforcer rate
    • Measurement of verbalized PREE
cognition in pree2
Cognition in PREE

Prediction of persistence:

”How likely is it that you will continue

responding if reward no longer appears?”

Several experiments have

demonstrated no sensitivity

to learning history in

predictions

slide46

3 extinction trials;

immediate behavioral

sensitivity

No difference

in predictions

Svartdal & Silvera, in prep.

cognition in pree3
Cognition in PREE

Retrospective judgments:

”How many responses did you emit after

reward no longer appeared?”

Subjects are very accurate in descrbing their own behavior, including their own extinction persistence

cognition in pree4
Cognition in PREE

Svartdal, F. (2003). Extinction after partial reinforcement: Predicted vs. judged persistence.Scandinavian Journal of Psychology, 44, 55-64.

meta cognitive pree
Meta-cognitive PREE?
  • We all have long experience with various contingencies
  • Maybe a ”meta-cognition” evolves:
    • Uncertain outcomes  Persist
    • Certain outcomes  Quit
meta cognitive pree1
Meta-cognitive PREE?
  • Scenarioes presented to subjects, manipulation
    • Reliable outcome vs.
    • Unreliable outcome
  • Persistence judgments of behavior
meta cognitive pree2
Meta-cognitive PREE?

Naive students: No effect of

outcome manipulation

meta cognitive pree3
Meta-cognitive PREE?

Psychology students

(have read about PREE)

Naive students

meta cognitive pree4
Meta-cognitive PREE?

Svartdal, F. (2000). Persistence during extinction:

Are judgments of persistence affected by contingency

information? Scandinavian Journal of Psychology,

41, 315-328.

pree theory
PREE: Theory

Mowrer & Jones: Diskriminasjonshypo- tesen

  • PRF:
    • Læringbetingelsene  ekstinksjonsbetingelsene
    • Generalisering til ekstinksjon
  • CRF:
    • Læringbetingelsene # ekstinksjonsbetingelsene
    • Liten generalisering til ekstinksjon
pree theory1
PREE: Theory

Amsel: Frustrasjonshypotesen

  • PRF:
    • Forventning om belønning  frustrasjon når belønning uteblir
    • Frustrasjons-cues assosieres med læringssituasjonen
    • Under ekstinksjon: Frustrasjon pga uteblitt belønning
    • Læringssituasjonen  ekstinksjonssituasjonen
  • CRF:
    • Frustrasjon oppstår ikke under læring
    • Læringssituasjonen # ekstinksjonssituasjonen
pree theory2
PREE: Theory

Capaldi: Sequential hypothesis

  • PRF:
    • Ikke-belønnede trials blir signal på at belønning snart vil følge: … N N N R N N N R …
    • Dvs.: Det opparbeides en forventning om belønning når belønning uteblir
    • Under ekstinksjon: Mange responser pga forventning om belønning
  • CRF:
    • Ingen erfaring med uteblitt belønning under læring
    • Under ekstinksjon: Få responser
pree theory3
PREE: Theory
  • Status:
    • Diskriminasjonshypotesen står svakt
    • Amsels hypotese står rimelig sterkt
    • Capaldis hypotese står ganske sterkt
    • Nevins modell: Ingen hypotese i vanlig forstand
  • Discrete-trial-situasjonen
    • Capaldi og Amsel dominerende
  • Fri-operant-situasjonen
    • Svak teoretisk forståelse