Download Operant Conditioning, 1

Chapter 8
Operant Conditioning
The sea lions are trained using operant conditioning,
emphasizing positive reinforcement.
Classical vs. Operant
Conditioning
CLASSICAL
OPERANT
•  Stimulus + Stimulus
à Response
•  Stimulus precedes
the response and
elicits it
•  Passive learning
•  Learning as a result
of association
•  Pavlov & Watson
•  Response + Stimulus
à Response
•  Stimulus follows the
response and
strengthens it
•  Active learning
•  Learning as a result of
consequences
•  Skinner
Operant Conditioning
§  Operant Behavior
§  operates (acts) on environment
§  produces consequences
§  Respondent Behavior
§  occurs as an automatic response to
stimulus
§  behavior learned through _______
conditioning
Operant Conditioning
§  Operant Conditioning
§  form of learning in which responses come
to be controlled by their consequences
§  Thorndike’s Law of Effect
§  if a response in the presence of a stimulus
leads to satisfying effects, the association
between the stimulus and the response is
strengthened
Operant Conditioning
“Operant conditioning shapes behavior as a sculptor shapes a
lump of clay.” -- B.F. Skinner 1974
§  B.F. Skinner
(1904-1990)
§  elaborated
Thorndike’s Law
of Effect
§  developed
behavioral
technology (incl.
the “Skinner Box”)
Operant Chamber
§  Skinner Box
§  chamber with a
bar or key that an
animal
manipulates to
obtain a food or
water reinforcer
§  contains devices
to record
responses
Operant Conditioning
§  Shaping
§  the
reinforcement
of closer &
closer
approximations
of a desired
response
§  Reinforcer
§  any event that
strengthens
the behavior it
follows
Process
Positive
Reinforcement
Negative
Reinforcement
Consequence
Effect on
Behavior
Response
Press lever
Rewarding
stimulus
presented
food delievered
Tendency to
press lever
increases
Response
Press lever
Aversive
stimulus
removed
Shock turned
off
Tendency to
press lever
increases
Behavior
Principles of
Reinforcement
§  Primary Reinforcers
§  events that are inherently reinforcing
because they satisfy a biological need
§  Secondary (Conditioned) Reinforcers
§  events that acquire reinforcing qualities by
being associated with primary reinforcers
Schedules of
Reinforcement
§  Schedule of Reinforcement
§  determines which occurrences of a specific
response result in the presentation of a
reinforcer
§  Continuous Reinforcement
§  occurs when every instance of a designated
response is reinforced
§  Intermittent (Partial) Reinforcement
§  occurs when a designated response is
reinforced only some of the time
Schedules of
Reinforcement
§  Fixed Ratio (FR)
§  reinforces a response only after a specified
number of responses
§  faster you respond the more rewards you get
§  very high rate of responding (but tiring)
§  like piecework pay
Schedules of
Reinforcement
§  Variable Ratio (VR)
§  reinforces a response after an
unpredictable number of responses
§  reinforcers may increase as the
number of responses increases
§  like gambling, fishing
§  very hard to extinguish because of
unpredictability
Schedules of
Reinforcement
§  Fixed Interval (FI)
§  reinforces a response only after a
specified time has elapsed
§  response occurs more frequently as
the anticipated time for reward
draws near
Schedules of
Reinforcement
§  Variable Interval (VI)
§  reinforces a response at unpredictable
time intervals
§  produces slow steady responding
§  like pop quiz
Schedules of Reinforcement
Reinforcement Schedules
•  Continuous
•  1 to 1 ratio, a prize every time
•  Ratio
•  comparison (usu. of objects)
•  fixed: 1 to ?, a prize every ? time
•  variable: ? to ?, maybe a prize, maybe not!
•  Interval
•  time specific
•  fixed: announced examination
•  variable: pop quiz