Transcript Results

Operant Conditioning – Ch. 9
October 26, 2005
Class #27
Analyzing Mild Punishment…
 Skinner (1938)
– Trained rats to barpress for food
– Extinction: One group of rats were punished
 Paw was slapped by experimenters (ouch!)
– Results:
 Behavior was suppressed…
 But, later that same day the punished rats caught up
to the unpunished group
– Skinner’s conclusion:
 Punishment was not effect
Boe and Church (1967)
 Replicated Skinner’s experiment but used
varying levels of punishment…
– Results:
 Mild shocks to cats resembled Skinner’s
 But, intense shocks produced much different results
– Boe and Church’s conclusion:
 Punishment was effective if done with sufficient
severity
Real World problems with this…
 Mild or ineffective punishment is then
switched to stronger punishment…
– Be careful…
Does punishment work???
 Martin (1977)
– Procedures:
 Boys worked on series of tasks
 Depending on type of task the boys were either
praised, reprimanded, or ignored
– Results:
 Later, boys worked harder on which task???
– In presence of instructor?
– In absence of instructor?
Experimental Neurosis
 Masserman (1943)
– Procedure:
 Cats given unpredictable electric shocks or blasts of
air while eating
– Results:
 Quiet cats became agitated
 Conditioned phobia
Applications…
 Generalized Anxiety Disorder
 PTSD
Preparedness & Operant
Conditioning
 Evidence for biological constraints in operant conditioning
 Bolles (1970)
– Animals cannot be trained to give any behaviour for any
reward
 Rats can easily be trained to lever-press to receive
food rewards (they have evolved high level use of
their paws to forage for food)
 Rats cannot easily be trained to lever-press to
escape shock (natural reaction to fear is run or
freeze)
– Training difficulties can be explained by animal’s
evolutionary history
Preparedness & Operant
Conditioning
 Biological dispositions in pigeon avoidance responses
– Pigeons can be easily trained to peck a disk for food
– Pigeons cannot easily be trained to peck a disk to avoid
shock
– Pigeons can be easily trained to flap their wings to
escape an electric shock
– Pigeons can not easily be trained to flap their wings to
get food
 It seems that some behaviours are naturally associated
with certain types of need
Preparedness & Operant
Conditioning
 Bolles (1979)
– Preparedness plays an important role in avoidance
behaviour
– Avoidance responses not operants (controlled by
consequences) – seem to be elicited behaviours
(controlled by stimuli that precede them)
Example
A rat’s natural reaction to fear is to freeze or to run and these
behaviours are naturally elicited. In a Skinner box a rat will
sometimes freeze when a shock is signalled (adaptive…ensures the
rats receives the shock?). If a rat experiences fear in a confined
space it cannot escape so its best defence is to freeze
Operant-Pavlovian Interactions
 Instinctive drift
 Sign tracking
Operant-Pavlovian Interactions
 Instinctive drift
– A classically conditioned fixed action pattern displaces an
operant behaviour
– Breland & Breland (1961)
 Attempted to train a pig to drop a coin in a piggybank
 Early conditioning was effective (eager pigs!!!)
 BUT…pigs began to drop coin and push it with nose
 Perhaps pig wasn’t hungry enough…food deprivation
was increased  misbehaviour worsened
– Pigs had associated the coin with food and began treating
it as though it was food
– Learned behaviour drifts towards instinctive behaviour
Operant-Pavlovian Interactions
Demonstration
 Coin (SD) : Deposit Coin (R)  Food (SR)
 Coin (CS) : Food (UCS)  Rooting (UCR)
 Coin (CS)  Rooting (CR)
 Pigs had associated the coin with food and
began treating it as though it was food
– Learned behaviour drifts towards instinctive
behaviour
Operant-Pavlovian Interactions
 Sign tracking
– The organism approaches a stimulus that signals the
likelihood of an appetitive event
Operant-Pavlovian Interactions


Food Dish


Light signals delivery of food
Pigeon should go to food dish & wait
Instead…pigeon approaches & pecks light!!!
Autoshaping (Brown & Jenkins, 1968)
 Pigeons - light key (8s) + non-contingent food
delivery
 No need to peck at key but do anyway
 Key Light : Food  Peck
 Key Light  Peck (Pavlovian response)
 Associate key with food
 Key Light : Peck  Food (operant response)
Key Light Signalling Food