Title: Principles of Behavior Sixth Edition
1Principles of BehaviorSixth Edition
Richard W. Malott Western Michigan University
Power Point by Nikki Hoffmeister
2Chapter 17
Ratio Schedules
3What is a Schedule of Reinforcement?
- Schedule of Reinforcement
- The way reinforcement occurs
- because of the number of responses,
- time between responses,
- and stimulus conditions.
4What is Continuous Reinforcement?
- Continuous Reinforcement (CRF)
- A reinforcer follows each response.
- Intermittent Reinforcement
- Reinforcement occurs, but not after each
response.
5When should you use CRF?
- Continuous reinforcement is usually best for
shaping or maintaining difficult behavior. - Shaping vocal responses
6What is a Fixed-Ratio Schedule?
- Fixed-Ratio (FR) Schedule of Reinforcement
- A reinforcer follows
- a fixed number of responses.
7What 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.
8Non-Cumulative Graph
9Non-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
10Post-Reinforcement Pause
- Characteristic of fixed-ratio-maintained behavior
- The length of the pause is proportional to the
size of the ratio
11High 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.
12What 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.
13The Cumulative Graph
14Cumulative 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.
15What is a Variable Ratio Schedule?
- Variable-Ratio (VR) Schedule of Reinforcement
- A reinforcer follows
- after a variable number of responses.
16What 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.
17VR 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
18Reinforcer 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
19Reinforcer 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
20Ratio Schedules in Everyday Life
- Are slot machines in casinos examples of everyday
VR schedules? - No there are 5 reasons why
214 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
224 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
234 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
244 Reasons Why Slot Machines are Not VR Schedules
- The emotional reaction is itself reinforcing
- Near misses are reinforcing
25Intermediate 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
26Discrete-Trial Procedure
- There is an SD,
- a single response,
- and an outcome,
- followed by an S? (intertrial interval)
- then the next trial starts.
27In 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
28In 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.
29Discrete 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
30Advanced Enrichment
- Hybrid Discrete-Trial/Free-Operant Procedure
- Each free-operant response, itself, consists of a
discrete trial.
31Example
- 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.
32Why 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).
33On DickMalott.com
- Chapter 17 Advanced Enrichment Section
- In Search of the Everyday Variable Ratio
34Join us for Chapter 18Interval Schedules