Download Aversive Control

Aversive Control
• Punishment
• Negative Reinforcement
– Escape Learning
– Avoidance
“Positive” Punishment
S R
OAversive
Positive Relationship
p(O/R) > p(O/noR)
Skinner’s Experiment on Punishment
Stage 1:
Rats were reinforced with food on a VI schedule
Stage 2:
Extinction for two successive days
First 10 min of extinction:
One group of rats was punished
Another group was not punished
Skinner concluded that punishment was not an effective way
to control behavior.
Increasing Effectiveness
 intense/prolonged from start
 response contingent rather than response
independent
 immediately after the response rather than
delayed
 continuous rather than partial
reinforcement schedule
Increasing Effectiveness
 punished response is not otherwise being
reinforced
 there is an alternative response to acquire
reinforcer
 the punished response is not a species-specific
defence reaction
unsignaled
Problems
person associated with punishment becomes
aversive (40 to 1 rule)
 general suppression of responding
 imitation of the aggressive behavior involved in
punishment
 escape/avoidance or aggressive responses
in punishing situation (aka “vicious circle”)
identifying punishers is difficult
(attention might be positive)
Escape/
Avoidance
Negative Reinforcement
Removes
S R
OAversive
Negative Relationship
p(O/R) < p(O/noR)
Note: if R removes OAversive = Escape
if R prevents OAversive = Avoidance
Signaled Escape And Avoidance
Light =
CS
Gridshock=
US
Rat Shuttle Box
Signaled Escape
Warning CS
Shock US
Shuttle
Time
Signaled Avoidance
Warning CS
Shock US
Shuttle
Time
Unsignaled (Sidman) Avoidance
S-S interval:
R-S interval:
20 s
40 s
60 s
Avoidance Puzzle
Question: How can the absence of an event act as
a reinforcer?
Answer: Something tangible has happened. Fear
is removed inside the organism.
The Two-Process Theory of Avoidance
1. (Pavlovian): Pairings of situational CSs with an
aversive US cause a fear CR to develop
2. (Instrumental): Responding causes removal of
the CS, which in turn removes the fear CR
Avoidance learning is escape learning; the organism
learns to escape from the CS and the fear that it elicits.
Is Conditioned Fear Termination As a
Reinforcer?
Stage 1
Stage 2
CS-US
Conditioning
Escape
ToneShock
Shuttle Tone Off
Challenges for the Two-Process Theory
1. “Unsignaled” avoidance
2. Avoidance does not readily extinguish
3. Level of fear is not always positively correlated
with avoidance
Fear in Active Avoidance?
Fear declines with trials
Stage 1
Active
avoidance
training
Stage 2
Does
warning CS
suppress
lever
pressing?
Answers from the Two-Process Theory of
Avoidance
1. Temporal conditioning and conservation of fear?
2. Response as a stimulus that inhibits fear (safety
signal)?
3. Well learned response trigger by very small
amounts of fear?
4. Response blocking will cause fear increase?
Alternative Theoretical Accounts of Avoidance
Behavior
Species-Specific Defense Reactions (SSDRs)
 more concerned with the actual response
 aversive stimuli elicit strong innate responses
(e.g., freezing, flight to dark area, fighting)
 species typical responses are readily learned as
avoidance responses (e.g., jump = two
trials versus lever-press = 1000s of trials)
 punishment originally thought to be responsible
for the selection of the avoidance response