Outline

1

• Outline
• B.F. Skinner
• Biography
• Theoretical notions
• Respondent and Operant Behaviour
• Operant Conditioning Principles
• The Skinner Box
• Shaping and Extinction
• Superstitious behavior
• Discriminative responding
• Secondary reinforcers

2

• Biography
• Wanted to be writer
• B.A. in English Literature (1926)
• Entered graduate school at Havard (1928)
• Mentored by the Chair of Physiology (W. Crozier)
• Who studied the animal as a whole without
  appealing to internal processes.
• Obtained his Ph.D. in 1931
• Taught at University of Minnesota (1936 - 1945)
• Published The Behaviour of Organisms (1938)
• Affiliated with Havard until he died (1990)

3

• Biography
• Inventions
• The air-crib
• Easily-cleaned, temperature and
  humidity-controlled
• Somewhat controversial (but effective)
• Commercially manufactured
• Project pigeon
• Received a 25K grant to develop a cruise missile
• Guided by trained pigeons
• U.S. Navy passed on it
• (but retested the idea
• in the 1980s)

4

• Biography
• Inventions
• The Skinner Box (AKA, operant chamber)
• Animal can respond multiple times
• Operant response Bar pressing
• Operant conditioning Increased bar pressing when
  food is delivered following the response.

5

• Biography
• Inventions
• Cumulative recorder
• Keeps track of the animals responding
• Time is recorded on the X axis
• Total number of responses is recorded on the Y
  axis
• Faster rates of responding lead to steeper slopes

6

• Major Theoretical Notions
• Respondent and operant behaviour
• Respondent behaviour - Behaviour elicited by a
  known stimulus
• E.g., Unconditioned responses
• Elicited by unconditioned stimuli
• Reflexive
• Operant behaviour - Behaviour not elicited by a
  known stimulus
• E.g., Most of our everyday behaviour
• Occurs spontaneously

7

• Major Theoretical Notions
• Type S and Type R conditioning
• Two kinds of conditioning
• Type S (respondent conditioning) - classical
  (Pavlovian) conditioning
• S to emphasize the role of the eliciting
  Stimulus
• Strength is measured by the magnitude of the CR
• Type R (operant conditioning) - learning that
  involves operant behaviour
• R to emphasize Response
• Strength is measured by the response rate

8

• Major Theoretical Notions
• Type S and Type R conditioning
• Comparison with Thorndikes approach
• Thorndikes puzzle box
• Dependent variable was time-to-solution
• -gt I.e., how long it took to learn a (single)
  response
• Skinner
• Dependent variable was rate of responding
• -gt I.e., What variables affect the rate
• of responding

9

• Major Theoretical Notions
• Operant conditioning principles
• Two general principles
• Any response that is followed by a reinforcing
  stimulus tends to be repeated
• A reinforcing stimulus is anything that increases
  the rate with which an operant response occurs
• I.e., anything that increases the probability of
  a responses re-occurring

10

• Major Theoretical Notions
• Operant conditioning principles
• Contingent reinforcement
• Emphasis on behaviour and its consequences
• Gaining reinforcement depends (i.e., is
  contigent) on making the appropriate response
• Culture as a set of reinforcement contigencies
• Different cultures reinforce different behaviour
  patterns
• Controlling reinforcement -gt controls behaviour
• E.g, child rearing

11

• Major Theoretical Notions
• Conditioning the lever-pressing response
• Three steps
• 1. Deprivation
• Food/water deprived for 23 hours per day
• Animal is held at 80 of its free-feeding body
  weight
• 2. Magazine training
• Food pellets are delivered by the experimenter
• Animal learns to associate the sound of the
  delivery mechanism with food

12

• Major Theoretical Notions
• Conditioning the lever-pressing response
• Three steps
• 3. Lever pressing
• Animal is placed in the box
• Eventually hits the lever (operant response)
• Delivery of food pellet reinforces the response.

13

• Major Theoretical Notions
• Conditioning the lever-pressing response
• Shaping
• A faster method of teaching the rat to lever
  press
• Two components
• 1. Differential reinforcement
• -gt Some responses are reinforced, others are not
• 2. Successive approximations
• -gt Only reinforce responses that become
  progressively closer to the desired response

14

• Major Theoretical Notions
• Extinction and spontaneous recovery
• Extinction - removing the reinforcer removes the
  operant response
• Spontaneous recovery - The reoccurrence of a
  response that had been extinguished, with no
  additional training.

15

• Major Theoretical Notions
• Superstitious behavior
• What if we delivered pellets noncontingently?
• Random behaviour would get reinforced
• E.g., Dog running in circles while waiting to get
  fed
• Humans are susceptible to similar conditioning
• E.g., Athletes/ coaches game rituals

16

• Major Theoretical Notions
• Discriminative operant
• Skinner box is set so that reinforcement is only
  available when the light is on.
• The light is the discriminative stimulus
• I.e., indicates that reinforcement is available
• SD light on, SD light off, SR reinforcing
  stimulus
• A discriminative operant is symbolized as
• SD -gt R -gt SR
• Skinner was interested in the SD -gt R association
• -gt Cf. respondent conditioning
• Stimulus control of behaviour

17

• Major Theoretical Notions
• Secondary reinforcement
• A neutral stimulus paired with a reinforcer can
  take on reinforcing qualities of its own
• To test this notion
• Lever press -gt light -gt food
• Extinguish the response
• Neither light nor food is delivered
• Allow lever - press to deliver light (not food)
• Response rate increases

18

• Major Theoretical Notions
• Secondary reinforcement
• A secondary reinforcer can be used to reinforce
  other responses
• Clicker training for dogs
• Warning secondary reinforcers can be
  extinguished!
• Money for humans
• Generalized reinforcer