Chapter 10 – Aversive Control: Avoidance and Punishment
• Outline
– Active Avoidance vs. Passive Avoidance
• Negative Reinforcement vs. Positive Punishment
– Avoidance
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•
•
•
Origins of the Study of Avoidance
Discriminated Avoidance (Signaled Avoidance)
Mowrer’s Two-Factor Theory of Avoidance
Experimental Analysis of Avoidance Behavior
– Acquired Drive Experiements
– Extinction of Avoidance
– Nondiscriminated (Free-Operant) Avoidance
– Punishment
• What is Punishing?
• Is Punishment Effective?
• Rules of Punishment
• Avoidance procedures increase the
occurrence of instrumental behavior
– Active avoidance
• Negative Reinforcement (Escape or Avoidance)
– Learn to make a response to avoid a negative outcome
• Punishment procedures suppress
instrumental responding
– Passive avoidance
• Positive Punishment
– Learn to withhold responding to avoid a negative
outcome.
• Origins of the study of avoidance
– Vladimir Becherev (1913)
• Participants were asked to put their finger on a
metal plate.
– tone (CS) was followed by a shock (US) through the
metal plate
– Participants quickly learned to pick up their finger
(CR) when they heard the tone (CS).
• This was considered to be a standard example of
classical conditioning.
– But it was different
• Removing finger cancelled the US
– avoidance
• Brogden, Lipman, and Culler (1938)
– Directly compared classical conditioning to avoidance learning
• Guinea pigs in a running wheel.
– CS- tone
– US – shock
• The shock stimulated the guinea pigs to run (UR)
• Gp1
• Classical
• US always followed
the tone
Gp2
Avoidance
US followed the tone
unless the Guinea’s ran
• The Avoidance group ran much more than the classically
conditioned animals.
• Discriminated Avoidance procedure
(signaled avoidance procedure)
– There is a warning stimulus (CS)
– What happens after the CS depends upon
what the animal does.
– Escape Trial
• Don’t respond fast enough
– US is presented until response is made
– Successful Avoidance Trial
• Respond quickly enough
– CS is turned off and there is no US on that trial.
• During early training most trials are
escape trials
• eventually the animals learn to make the
avoidance response, and then avoidance
behaviors take over.
• These experiments have often been
performed in shuttle boxes.
• Shuttle avoidance
– Two-way
• move back and forth.
– One-way
• always start each trial on one side
– move to the other.
• Mowrer’s two factor theory of Avoidance.
– The problem for avoidance tasks is that once animals are
performing well, the outcome (shock) doesn’t occur anymore
• Looks like extinction
• So what motivates responding?
• Pavlovian (emotional conditioning)
– Signaled
• CS – US
• Instrumental
– After fear is conditioned the second thing that is learned is the
instrumental response (jump barrier).
• What motivates responding?
– Negative RF
– escape from conditioned fear.
• Experimental Analysis of Avoidance Behavior
• Acquired drive experiments
– In the typical avoidance procedure the classical conditioning,
and instrumental conditioning, occur simultaneously.
– But if two-factor theory is correct it should be possible to train
these two kinds of learning separately.
• 1) condition fear to a CS with a pure classical conditioning
procedure.
– CS (tone) --> US (shock)
– CR (fear)
• 2) the animals are periodically presented with the CS, but an
instrumental response can prevent it.
– No shocks are delivered in phase 2.
• Brown and Jacobs (1949).
• Classical conditioning
• Confined rats in one side of a shuttle box – the shuttle
opening was blocked.
– Light/tone (CS) --> shock (US).
• 22 trials.
• Instrumental conditioning
• The shuttle box opening was opened.
• CS came on, and remained on until the rats went to the other
side – escape.
– The animal was removed until the next trial.
• Over time the shock conditioned animals learned to cross
over to the other side sooner after the initiation of the CS.
• Do we need a control group?
• Extinction of Avoidance?
– Solomon, Kamin, and Wynne (1953)
• One dog avoided shock for 650 straight trials after
escaping a few.
– Is it possible to extinguish?
• Flooding or Response Prevention
– Participant is prevented from making the
instrumental response during CS
• The US is omitted (extinction)
– Block off door to shuttle box
• CS alone
• Has clinical implications
– Help people extinguish pathological avoidance
• Learn to avoid anxiety producing situations.
• Nondiscriminated (Free-Operant)
Avoidance
– Executive Monkey
• Press key every 15 seconds to avoid shock.
– S-S interval – time between shocks if you don’t respond
– R-S interval – period of safety created if you do respond
» Don’t have to be the same.
» S-S 8s
» R-S 15s.
– you will receive a shock every 8s unless you respond.
– If you do respond you buy yourself 15s in the absence of
shock.
• Chimps have been trained with several
schedules to keep track of to avoid shock
(Koestler & Barker, 1965).
– respond every 5-s on a button to avoid shock
(Free operant avoidance)
– any key that lit up with a light (Sd) had to be
pressed within one second or they would be
shocked (Signaled Avoidance).
– a separate unlit key had depressed within one
second of a second Sd ( a tone; Signaled
Avoidance)
– The Chimps were able to keep track of all of this
at once
• motivated by fear?
•
So Fear motivates responding?
– Kamin, Brimer, and Black ran an experiment that showed that this may not be the
case.
– Conditioned Suppression
•
Phase 1
– Rats trained to barpress for food
•
Phase 2
– Then put into a shuttle box where a tone Sd set the occasion to jump the barrier to
avoid shock
– There were four groups (they differ in amount of training)
•
•
•
•
•
group 1 = avoid shock by jumping barrier on 1 trial
group2 = avoid shock by jumping barrier on 3 consecutive trials
group 3 = avoid shock by jumping barrier on 9 consecutive trials
group 4 = avoid shock by jumping barrier on 27 consecutive trials
Test
– returned to the operant chamber
•
•
continued to barpress for food.
The tone was sounded
• Rats that had reached the 1, 3, or 9 consecutive trial criterion,
showed considerable suppression when the tone sounded.
– Fear tone.
• surprisingly the rats that had had 27 consecutive trials of
avoidance did not suppress responding.
– It seems that increasing experience with the situation lessens
the fear.
– especially because the animals have learned they have control
over the situation.
• Think of an air traffic controller.
– are they motivated by negative reinforcement?
– are they afraid all of the time?
– are they only afraid when they think they have made a mistake?
• Nevertheless Two- Factor theory is the theory of avoidance
against which all others are compared.
• Punishment
– As we have already discussed. Punishment is some manipulation that
causes a decrease in responding
• As a society we tend to be very interested in punishment
– Crime
– Children
• Is Punishment effective?
• Skinner initially argued that Punishment was not very effective
– Possibly came to this conclusion because he was using weak punishers
• Electronic slap of the paw
– It has been shown that punishment can be effective if the correct
conditions are met
• Domjan’s example
– Ticket for speeding
– Child sticks fork in electric socket.
• Experimental Analysis of Punishment
– Punishment involves decreasing a behavior
• in order to measure it you must initially have a baseline of that
behavior
– In real life or therapeutic situations punishment is used to
decrease some maladaptive behavior
• Self injurious behavior
• Drug taking
– In the lab, we typically first train the animals to perform a
behavior
• Then introduce punishment to see if it suppresses responding
• This can make things complicated
– Is responding more influenced by reward or punishment?
» It depends
» Skinner’s paw slap
• Characteristics of the Aversive Stimulus
and its Method of Introduction
• Types of Stimuli
– Remember one form of punishment (positive
punishment) involves presentation of an
aversive stimulus
•
•
•
•
Shock
Loud noise
slap
Squirt of lemon juice in the mouth
• negative punishment involves taking away
something the organism wants
– Loss of positive RF
– Time out
• Removal of personal freedoms
– Can’t get typical RF
• When is Punishment most effective?
– Let’s go through what could be considered the “Rules
for Effective Punishment”
– This list is backed up by empirical findings from the
animal literature
• Think about how we often don’t follow these rules in real life
though
• 1) punishment must be delivered soon after a
response to be most effective
– “Catch them in the act”
• Delayed punishment is far less effective
– Can work well with your dog or cat.
• Kids?
• Criminals?
• 2) Punishment must be strong as possible
to be effective
– Mild shock causes only moderate suppression
of behavior
• The effect of mild shock dissipates with repeated
application
– Habituation
– Intense, longer lasting shocks are far more
effective
• Kids?
• Criminals?
• 3) Punishment must be delivered
consistently to be effective.
– Punishment works best if it is applied every
time
– How does this compare to the effects of
partial reinforcement?
• Kids?
• Criminals?
• 4) Punishment should be as strong as
possible initially
– It is not very effective to start off weak and
then increase with repeated infractions.
• Kids?
• Criminals?
• 5) Response-Contingent versus
Response-Independent Aversive
Stimulation
– Random punishment can suppress
responding.
• Especially if intense
– Learned helplessness
– Typically, however, random punishment is not
as effective as contingent punishment
• With random punishment in a rat you might see
some initial decline in responding
– but as the animal becomes used to it responding tends to
increase
• 6) noncontingent punishment decreases
the effectiveness of contingent punishment
– If animals are shocked at random initially they
take longer to associate shock with a specific
stimulus, or response.
• Phase 1: Random shocks
• Phase 2: Lever press = shock
– US preexposure effect
• Kids?
• Criminals?
• 7) Punishment is more effective if animal if offered an alternative
response to the punished response
– Herman and Azrin (1964)
• Human smokers
• Two levers
• Phase1 (Training)
– Lever 1: cigarette VI schedule
– Lever 2: cigarette VI schedule
• Phase 2 (Test)
– Condition 1
• Lever 1: loud noise; cigarette VI schedule
• Lever 2: cigarette VI Schedule
– Condition 2
• Lever 1: loud noise; cigarette VI schedule
• Findings?
– How much pressing of lever 1?
• Condition 1?
• Condition 2?
• The findings from Herman and Azrin (1964) may
seem obvious, but the implications are important
• If you want to discourage a particular behavior, you
can punish it.
– But it would be more effective to punish that behavior while
providing the organism alternative reinforcing/reinforced
behaviors
» Punish playing too much x-box, but supply lots of new
books/magazines?
» Punish self-injurious behavior, but supply other activities
(painting, music, social interaction).
– Providing alternative behavioral opportunities
can make even mild punishment much more
effective.
• 8) Punishment can come under stimulus control
– Discriminative punishment
• Responding is punished in the presence of an S+
– Light indicates lever pressing will result in shock
– Otherwise responding is RF
» Animals quickly learn not to respond to the lever when a light
is on.
• Kids?
– Parent present or not
– Classroom effects
• Teacher present
• Substitute/weak teacher
• Criminals?
– Police car  speeding
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Chapter 10: Aversive Control: Avoidance and Punishment