Aversive Control: Avoidance and Punishment

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Aversive Control Avoidance and Punishment
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Avoidance/Escape

• Escape getting away from an aversive stimulus in
  progress
• Avoidance preventing the delivery of an aversive
  stimulus
• Negative contingency between response and
  aversive stimulus
• Increase in operant responding

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Brogden et al. (1938)

• Guinea pigs
• CS tone, US shock, UR pain, CR running
• Classical conditioning group
• CS followed by US
• Avoidance group
• CS -- CR --gt no US
• CS -- no CR --gt US

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Discriminative Avoidance

• Stimulus signals onset of aversive US

Avoidance
Escape
CS
CS
US
US
R
R
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Shuttle Box

• Standard experimental paradigm

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Escape

• In presence of aversive stimulus
• Make response
• Aversive terminated
• Negative reinforcement

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Avoidance Paradox

• Make response before aversive delivered
• Behaviour clearly increases, so reinforcer
• But what is taken away (or delivered)?
• Mowrer Lamoreaux (1942)
• not getting something can hardly, in and of
  itself, qualify as rewarding.

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Two-Process Theory

• Two mechanisms classical and instrumental
• 1. Classical conditioning process activated by CS
  when avoidance not made CR of fear produced
• 2. Negative reinforcement successful avoidance
  removes fear caused by CS
• Classical and instrumental conditioning processes
  are independent
• Avoidance escape from fear, not prevention of
  shock

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Acquired Drive Experiment

• Phase 1 condition fear to CS through classical
  conditioning procedure
• Phase 2 let subject make operant response to
  terminate CS
• No shock
• Drive to avoid learned through classical
  conditioning

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Brown and Jacobs (1949)

• Rats in shuttle box
• Experimental and control groups
• Phase 1 light/tone CS --gt shock
• Phase 2 CS --gt no shock turn CS off by crossing
  barrier
• Measure time to change sides
• Supports two-process theory
• Termination of fear CS drives operant response

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Rescorla LoLordo (1965)

• Dog in shuttlebox
• No signal
• Response gives safe time
• Pair tone with shock
• Tone increases rate of response
• CS can amplify avoidance
• CS- can reduce avoidance

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Problems for Theory

• Fear a necessary component
• Fear reduction with experience

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Kamin, Brimer Black (1963)

• Rats
• Lever press in operant chamber for food
• Auditory CS for shock avoidance in shuttle box
  until 1, 3, 9, 27 avoidances in a row
• CS in operant chamber check for suppression of
  lever press

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Alternation of Behaviour (Yo-yo)

• Every successful avoidance puts CS on extinction
• With extinction, fear drops, so motivation to
  avoid decreases
• Resulting in more shocks, strengthening CR again
  and increasing avoidance response
• But we dont really see this

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Persistence of Avoidance

• Sometimes a problem
• Phobias
• Need to extinguish avoidance
• Flooding, response prevention

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Sidman Free-Operant

• Can avoidance be learned without warning CS?
• Shocks at random intervals
• Response gives safe time
• Extensive training, but rats learn avoidance
  (errors, high variability across subjects)

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Hernstein Hineline (1966)

• Rapid and slow shock rate schedules
• Response switches from rapid to slow
• Shift back to rapid random so no time signal
• Response produces shock reduction

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Reduction of Shock Frequency

• Molar account
• Response reduces in amount of shocks over long
  run
• Negative reinforcement
• Overall shocks taken away, behaviour increases

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Safety Signals

• Molecular account
• Positive reinforcement
• Context cues associated with safety
• Either SD or CS-
• Making response gives safety
• Giving explicit stimuli makes avoidance learning
  easier

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SSDRs

• Species-specific defense reactions
• Innate responses evolved
• SSDRs predominate in initial stages of avoidance
• Hierarchy
• If first SSDR works, keep it
• If not, try next, etc.
• Aversive outcome (punishment) is the selector of
  appropriate avoidance response

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SSDRs

• Fight, flight, freeze
• Also thigmotaxis, defensive burying, light
  avoidance, etc.
• Environmental content influences selected SSDR
• E.g., freezing not useful if predator right in
  front of you
• Some responses easier to learn than others
• E.g., rats wheel run --gt avoid shock (easy)
• E.g., rats rear --gt avoid shock (hard)

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Predatory Imminence

• Different innate defensive behaviours at
  different danger levels

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Differences from SSDR

• 1. Behaviours in anticipation, not response
• 2. Predatory imminence, not environmental cues
  leads to response
• 3. Not selected via punishment

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Punishment

• Positive punishment
• Delivery of stimulus --gt reduction in behaviour
• Negative punishment
• Removal of stimulus --gt reduction in behaviour
• Time out
• Overcorrection

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Introduction of Punisher

• Effective use of punishment
• Tolerance
• Start with high(er) intensity
• Can then reduce and behaviour will remain
  suppressed

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Response-Contingent vs. Response-Independent

• Does your response cause the aversive outcome?
• More behavioural suppression if aversive stimulus
  produced by operant response

Phase 1 train on VI-60 sec
light
Phase 2 tone light FR-3 response-independe
nt punishment punishment
Yoked
tone
Suppression ratio
Trials
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Delay

• Interval between response and delivery of
  aversive
• Longer the delay, less suppression of behaviour

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Punishment Schedule

• Continuous or intermittent schedules
• Azrin (1963)
• Different FR punishment schedules responding
  maintained with VI reinforcement

no punishment
FR 1000
FR 500
Cumulative responses
FR 100
FR 5
Time
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Positive Reinforcement Schedules and Punishment

• Without some positive reinforcement, behaviour
  generally stops quickly
• As in previous study, responding maintained with
  appetitive outcome on VI schedule
• Interval
• Overall decrease
• VI suppressed but stable
• FI scalloping
• Ratio
• Increases post-reinforcement pauses

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Alternative Sources of Reinforcement

• Options
• No alternatives but punished behaviour
• Alternative behaviours (e.g., differential
  reinforcement schedules DRA, DRI, etc.)
• Availability of reinforceable alternatives
  increases suppression of punished response

no punishment
Punishment, no alternative response available
Cumulative responses
Punishment, alternative response available
Time
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SD for Punishment

• Suppression limited to presence of SD
• E.g., garden owl
• E.g., cardboard cops and kids

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Punishment as SD for Availability of Pos. Reinf.

• Sometimes punishment seeking behaviour
• Punisher becomes S for positive reinforcement
• E.g., masochism, children seeking attention

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CER Theory of Punishment

• Estes (1944)
• Conditioned suppression
• E.g., freeze prevents lever press
• CER incompatible with making response
• Punishment suppresses behaviour through same
  mechanism
• In real world, no explicit CS
• Stimuli immediately before punished response
  serve this function
• Estes (1969) incompatible motivational state

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Avoidance Theory of Punishment

• Tied to two-process theory
• Engage in incompatible behaivour
• Prevents making punished behaviour
• Strengthening of competing avoidance response
• Not weakening of punished response
• Same theoretical problems of avoidance

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Negative Law of Effect

• Thorndike (1911)
• Positive reinforcement and punishment are
  symmetrical opposites
• Similar to Premack Principle
• Low probability behaviours reduce high
  probability behaviours
• Forced to engage in low-valued behaviour after
  doing high probability behaviour