Transcript Theories and Applications of Aversive Conditioning

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THEORIES AND
APPLICATIONS OF
AVERSIVE CONDITIONING
Chapter 7
Escape, Avoidance, & Punishment
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
We usually respond to aversive events by either
 1)
making a response the will let us escape from the
aversive situation (Escape), or
 2) making a response that will let us avoid the aversive
situation (Avoidance), or
 3) stop doing something that caused an aversive
(Punishment)
Escape Conditioning
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
Escape response: a behavioral response to an
aversive event that is reinforced by the termination
of the aversive event
Escape Examples
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Pressing button
removes cold
Proposal Gone Bad
¼ wheel turn
terminates
a tail shock
AKA“Negative” Reinforcement
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S R
OAversive
Negative Relationship
p(O/R) < p(O/noR)
Escape from Aversive Events
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
Several factors play a role in determining whether
an organism learns to escape aversive events
 Intensity
of the aversive stimulus (facilitates learning)
 Absence of negative reinforcement (impairs learning)
 Impact of delayed reinforcement (impairs learning)

There are also many factors that affect the
efficiency of the escape response
Elimination of an Escape Responses
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
An escape response can be extinguished
 No
longer terminating the aversive stimulus following the
escape response
 However, the response will continue for some time until
the organism learns that the escape response no longer
terminates the aversive event
Vicious Circle Behavior
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
Vicious circle behavior: an escape response that
continues despite punishment, due to a failure to
recognize that the absence of the escape behavior
will not be punished
 It
occurs because the organism doesn’t realize that not
responding will not lead to punishment
The Avoidance of Aversive Events
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
Avoidance response: a behavioral response that
prevents a potential aversive event
 Active (Do something)
 Passive (Don’t do something)
Passive Avoidance Behavior
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
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Refers to avoiding a potential aversive by not
acting.
 Don’t jump off the10 meter diving board
In passive avoidance situations, the more severe the
aversive event, the faster the acquisition of the
passive avoidance response
One-Way Active (Subject Escapes)
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Warning CS
Shock US
Response
Time
One-Way Active (Subject Avoids)
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Warning CS
Shock US
Response
Time
Two-Way Active Avoidance Behavior
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
The organism is placed in one chamber (A) and
exposed to a cue before it is shocked
To avoid the shock, it must run to the other side (B)
before the shock is presented
After this, the animal remains in side B for a short
intertrial interval (ITI)
Two-Way Signaled Active
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Light= CS
Gridshock=
US
Rat Shuttle Box
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The stimulus is then presented again and the animal
must run back to side A
Thus, the animal avoids the shock by running back to
the place it was previously shocked
This model requires the animal to ignore situational
and contextual cues and pay attention to only one
cue (the signal)
Two-Way Unsignaled Active
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S-S interval:
R-S interval:
20 s
40 s
60 s
The Severity of the Aversive Event
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
In most cases, the greater the severity of the
aversive event, the more readily the subject will
learn the avoidance response
 The
final level of performance is also higher in most
cases
 Two-Way active avoidance is often impaired with
increasing intensity.
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
In the two-way avoidance model, learning is
inversely related to severity of shock
 That
is, the more severe the shock, the slower the
learning of the response
 This may be due to the fact that the animal experiences
conflict about going back into the place it was
previously shocked
 The
greater the shock, the greater the conflict
Avoidance Puzzle
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Question: How can the absence of an event act as
a reinforcer?
Answer: Something tangible has happened. Fear
is removed inside the organism.
Mowrer’s Two-Process Theory of Avoidance
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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 Fear Termination a Reinforcer?
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Stage 1
Stage 2
CS-US
Conditioning
Escape
ToneShock
Shuttle Tone Off
D’Amato’s Modification of Two-Process
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
D’Amato asserts that we are motivated to approach
situations associated with relief as well as to escape
events paired with aversive events
 The
relief experienced following avoidance behavior
rewards the response
 Removal of anticipatory pain (US) as well as
anticipatory fear (CS) might also play a role
Four Challenges for the Two-Process Theory
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1. “Unsignaled” avoidance
2. Avoidance does not readily extinguish
3. Level of fear is not always positively correlated
with avoidance (fearless avoidance)
4. Extinguish warning stimulus doesn’t always
eliminate avoidance
Fear in Active Avoidance?
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Fear declines with trials
Stage 1
Active
avoidance
training
Stage 2
Does
warning CS
suppress
lever
pressing?
Cognitive View of Avoidance
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
Calculation of what choice will likely yield a better
(less dangerous) situation
 Military
 PTSD
“Malingers”
Answers from Two-Process Theory of Avoidance
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1. Temporal conditioning
2. “Conservation of fear” (Response so quick the
feared stimulus not fully experienced)
3. Response as a stimulus that inhibits fear (safety
signal)
4. Well learned response trigger by very small
amounts of fear (habit learning)
5. “Response blocking” or “flooding” should
increase fear
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
Although flooding seems to be very effective, many
people do not want to participate in flooding
because the initial anxiety is so great
Alternative Theoretical Accounts of Avoidance
Behavior
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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
Punishment
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
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Punishment: use of an aversive event contingent on
the occurrence of an inappropriate behavior
The intent of punishment is to suppress an undesired
behavior
If punishment is effective the frequency, intensity, or
both will decline
THE NATURE OF PUNISHMENT
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
Thorndike’s Negative Law of Effect
 The
negative law of effect states that punishment
weakens the strength of an S-R bond
 The recovery of responding shortly after exposure to a
mild punishment contradicts this view because the
weakened bond should be permanent, not temporary
Skinner’s Experiment on Punishment
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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 (refutes “negative law of effect”).
The Effectiveness of Punishment
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
Punishment appears to suppress unwanted
behaviors
 However,

the suppression is often temporary
In some cases, however, punishment permanently
suppresses unwanted behaviors
Increasing Effectiveness
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 intense/prolonged from start (no ramping
up)
 response contingent rather than response
independent
 immediately after the response rather than
delayed
 continuous rather than partial
reinforcement schedule
Increasing Effectiveness
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 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
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person associated with punishment becomes
aversive (40 to 1 rule)
 general suppression of responding
 imitation of the aggressive behavior involved in
punishment; pain-initiated aggression
 escape/avoidance or aggressive responses
in punishing situation (aka “vicious circle”)
identifying punishers is difficult
(attention might be positive)
Types of Punishment
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
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Punishment is the response-contingent presentation
of an aversive event
Positive punishment: addition of an aversive event
(e.g. spanking) to reduce the undesirable behavior
Negative punishment: removal of an appetitive
event (watching TV) to reduce an unwanted
behavior (aka: omission)
Categories
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
There are two categories of negative punishment
 Response
cost: an undesired response results in either
the withdrawal of or failure to obtain reinforcement.
 Time-out from reinforcement (time out): a period of time
during which reinforcement is unavailable
Response Cost
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
Response cost:

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A negative punishment technique in which an undesired
response results in either the withdrawal of or failure to
obtain reinforcement
Response cost is a form of negative punishment
It refers to a penalty or fine contingent upon the
occurrence of an undesired behavior
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
Response cost has been used to successfully treat a
wide range of behaviors including:
 Self
mutilation
 Smoking
 Overeating
 Tardiness
 Aggressiveness
Time Out
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
Time out from reinforcement
A
negative punishment technique in which an
inappropriate behavior leads to a period of time
during which reinforcement is unavailable
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If a time out area is used, it must not be reinforcing