Principles of Behavior Sixth Edition

1
Principles of BehaviorSixth Edition
Richard W. Malott Western Michigan University
Power Point by Nikki Hoffmeister
2
Chapter 17
Ratio Schedules
3
What is a Schedule of Reinforcement?

• Schedule of Reinforcement
• The way reinforcement occurs
• because of the number of responses,
• time between responses,
• and stimulus conditions.

4
What is Continuous Reinforcement?

• Continuous Reinforcement (CRF)
• A reinforcer follows each response.

• Intermittent Reinforcement
• Reinforcement occurs, but not after each
  response.

5
When should you use CRF?

• Continuous reinforcement is usually best for
  shaping or maintaining difficult behavior.
• Shaping vocal responses

6
What is a Fixed-Ratio Schedule?

• Fixed-Ratio (FR) Schedule of Reinforcement
• A reinforcer follows
• a fixed number of responses.

7
What kind of responding does a fixed-ratio
schedule produce?

• Fixed-Ratio Responding
• After a response is reinforced,
• no responding occurs for a period of time,
• then responding occurs at a high, steady rate
• until the next reinforcer is delivered.

8
Non-Cumulative Graph
9
Non-Cumulative Graph

• The horizontal line (x-axis) indicates the
  passage of time
• Each vertical line indicates a response
• At the end of each ratio of 8 responses a
  reinforcer is delivered (indicated by star)
• After each star, the line is flat, indicating no
  response occurs for a while
• Post-reinforcement pause

10
Post-Reinforcement Pause

• Characteristic of fixed-ratio-maintained behavior
• The length of the pause is proportional to the
  size of the ratio

11
High Ratios

• If you wish to establish a high ratio
  requirement,
• you need to do so gradually,
• raising the ratio from 2 to 4 to 6 responses and
  up.
• Otherwise the response may extinguish.

12
What is the general rule for establishing
intermittently reinforced behavior?

• First, use continuous reinforcement
• and gradually increase the intermittency of
  reinforcement
• as responding stabilizes at a high rate.

13
The Cumulative Graph
14
Cumulative Graph

• Behavior analysts often use this type of graph
  when studying schedules of reinforcement.
• The vertical axis (ordinate) is labeled
  cumulative frequency of responses as opposed to a
  non-cumulative graph in which the ordinate is
  labeled responses.
• The post-reinforcement pause is where the slope
  of the line is zero.

15
What is a Variable Ratio Schedule?

• Variable-Ratio (VR) Schedule of Reinforcement
• A reinforcer follows
• after a variable number of responses.

16
What type of responding does a VR schedule
produce?

• Variable-Ratio Responding
• Variable-ratio schedules produce
• a high rate of responding,
• with almost no post-reinforcement pausing.

17
VR Schedules

• VR 50
• This means that a reinforcer is delivered after
  an average of 50 responses
• An FR 50 means the reinforcer is delivered after
  exactly 50 responses
• Intermittent Reinforcement
• Generic term that includes both fixed and
  variable ratio schedules

18
Reinforcer vs. Reinforcement

• What is a specific pellet of food for a deprived
  rat?
• A reinforcer
• Reinforcement
• The immediate delivery of a pellet contingent on
  a deprived rats lever press with a resulting
  increased rate of pressing?
• Reinforcer
• Reinforcement

19
Reinforcer vs. Reinforcement

• What is a quarter for a deprived professor?
• Reinforcer
• Reinforcement
• What is the immediate delivery of a quarter,
  contingent on a deprived profs pleading for a
  raise, with a resulting increased rate of
  pleading?
• Reinforcer
• Reinforcement

20
Ratio Schedules in Everyday Life

• Are slot machines in casinos examples of everyday
  VR schedules?
• No there are 5 reasons why

21
4 Reasons Why Slot Machines are Not VR Schedules

• Its loaded with learned reinforcers in addition
  to the silver dollars
• Like those fruits that appear in the window, one
  after the other
• You get 2 cherries in a rowa big reinforcer

22
4 Reasons Why Slot Machines are Not VR Schedules

• The variable amount of the reinforcer you get at
  the end of the so-called VR
• Sometimes you get only one silver dollar
• Sometimes its 10, 18, so on
• None of thats like the ratios the behavior
  analysts study in the Skinner box

23
4 Reasons Why Slot Machines are Not VR Schedules

• The size of the ratio is much smaller than is
  typical in the Skinner box of the professional
  research lab
• Like a VR 100
• In a casino, people would not play if machines
  had ratios of 100

24
4 Reasons Why Slot Machines are Not VR Schedules

• The emotional reaction is itself reinforcing
• Near misses are reinforcing

25
Intermediate Enrichment

• Free-operant procedures
• Most Skinner-box research involves free-operant
  responding
• The animal is free to respond at various
  frequencies (1 lever press per minute to 100
  lever presses per minute)
• There is no S? after each response, so there is
  no inter-trial interval between each response and
  the next SD

26
Discrete-Trial Procedure

• There is an SD,
• a single response,
• and an outcome,
• followed by an S? (intertrial interval)
• then the next trial starts.

27
In the ClassroomDiscrete-Trial Procedure

• SD Sue says, Jimmy point to the horse.
• Response Jimmy points to the horse.
• Outcome Sue says, Good boy, Jimmy. (a learned
  reinforcer for Jimmy)
• S? (Inter-trial Interval) Sue says nothing

28
In the ClassroomFree-Operant Procedure

• SD Sue and Jimmy at the snack table.
• Response 1 Jimmy says, Juice please.
• Outcome Sue gives him a sip of juice.
• Response 2 Jimmy says, Juice, please.
• Outcome Again, Sue gives him a sip of juice.
• S? Sue and Jimmy leave the snack table.

29
Discrete Trial vs. Free Operant
Discrete Trial Free Operant
Is there an SD and an S?? Yes Sometimes
Is there an inter-trial interval? Yes Usually not
The measure is Latency or accuracy Rate
30
Advanced Enrichment

• Hybrid Discrete-Trial/Free-Operant Procedure
• Each free-operant response, itself, consists of a
  discrete trial.

31
Example

• Sue and Jimmy are in the structured-play area
• Response 1 Jimmy picks up a piece of the puzzle
  and puts it in the puzzle form
• Response 2 Jimmy picks up a 2nd piece and puts
  it in the puzzle form
• Response 3 Jimmy picks up a 3rd, final piece,
  and puts it in the form
• Outcome Jimmy has completed the puzzle and sees
  a picture of Barney. Sue says, Good job.

32
Why Hybrid?

• This is an example of a discrete trial, because
  each piece Jimmy puts in the puzzle is an SD for
  the next response.
• It is also an example of free operant because
  Jimmy is free to place each puzzle piece as fast
  as he wants, and
• A measure of his behavior would be a rate measure
  (e.g., 8 pieces per minute).

33
On DickMalott.com

• Chapter 17 Advanced Enrichment Section
• In Search of the Everyday Variable Ratio

34
Join us for Chapter 18Interval Schedules