Mean = 13.25 = 83%

14.75

12

14.5

12

13

13.75

12.5

13.5

12.75

13

14

Schedules of Reinforcement

Chapter 13

• A schedule of reinforcement is a rule specifying…– the arrangement and response requirements for

reinforcement– e.g., whether a reinforcer follows every behavior, every

other behavior, etc.• 2 Simple Schedules

– Continuous Reinforcement (CRF; FR1)• The reinforcer follows every behavior• CRF results in rapid acquisition (good for teaching)• CRF produces little resistance to extinction

– Extinction (EXT)• Discontinuation of a response-reinforcer contingency

What’s a Schedule?

• Some rather than all responses are reinforced• Two main categories

– Ratio schedules: the reinforcer is delivered after every X behaviors

– Interval schedules: the FIRST behavior after X amount of time is reinforced

• Produces better resistance to extinction than CRF– Good for maintaining behavior

Intermittent Reinforcement

• 2 Types: Fixed Ratio and Variable Ratio

• Fixed Ratio: the reinforcer is delivered after a fixed number of behaviors

– Designation: FR 5 (every 5th target response is reinforced)

– Produces high-rate responding – why?

– Produces a post-reinforcement pause (PRP)

• PRPs are proportional to the size of the ratio

– e.g., piecework

Ratio Schedules

Fixed-Ratio Schedule of Reinforcement

SR+ delivered

PRP

Variable Ratio

• The reinforcer is delivered after an average number of behaviors

• Designation: VR 5– 5, 4, 7, 6, 4, 3, 6, 7, 3

• Produces consistent, high rates with no PRPs

• e.g., starting a lawn mower• Clinical applications…

Tic-Tac-Toe VR Procedure

• Teacher picks maximum number of responses for an individual or group (e.g., 30)

– The smaller the #, the more likely it is that the learner(s) will meet the contingency

• Learners fill in each square of tic-tac-toe grid with a # no greater than the max

• Teacher fills box with numbers on slips of paper

– Each number several times

• Contingent on target behavior, student picks slip of paper

– If on tic-tac-toe, cross out number

• Deliver SR+ when 3 in a row

27 5 23

11 15 9

3 20 10

5

Classroom Lottery VR Procedure

• Students write their names on index cards after successfully completing assigned tasks– Cards go in a box

• After a preset period of time (e.g., 1 week),…– Teacher picks a card – that student is the winner– The more cards earned, the more likely a student will be the

winner

Reggie

Lottery Box!

• Both FR and VR schedules have 2 major advantages– Produce high rates of responding– Easy to use

• Potential Disadvantage– Ratio strain can result from abrupt increases in

ratio requirements

Considerations with Ratio Schedules

• 2 Types: Fixed Interval and Variable Interval• Fixed Interval: the reinforcer is delivered for the

first target response after a fixed period of time has elapsed– Designation: FI 60s– e.g., turning on the TV to watch your favorite

show– Characteristics

• Produces PRPs, resulting in scallop or break-and-run patterns

• Slow to moderate rate of responding

Interval Schedules

SR delivered

PRP

• the reinforcer is delivered for the first behavior after an average period of time has elapsed– Designation: VI 60s– produces steady, moderate responding (no

PRPs)– e.g., checking e-mail

• Limited Hold: a feature that can be added to any interval schedule– The behavior must occur after the interval has

elapsed, but within a specific period of time– Designation: FI 5 min LH 30 s

Variable Interval Schedule

• Use if you want to produce low to moderate response rates

• Advantage– FI schedules are relatively easy to use with a

resetting timer

• Potential Disadvantage– Off-task or other unwanted behavior may occur

during the PRP

Considerations with Interval Schedules

Post-reinforcement pause

FI scallop

time

# re

spon

ses

• Schedule thinning: Gradually increasing the response ratio or the extent of the time interval

• Benefits– The student’s behavior becomes more durable

(more resistant to extinction)– More practical for caregivers to implement

• If you move too quickly, you can produce ratio strain– Aggression– Extinction of responding

• Not many guidelines are available to tell us how to do this

Thinning the Schedule of Reinforcement

LeBlanc, Hagopian, Maglieri, & Poling (2002)

• Determine a reasonable terminal goal that’s appropriate to the age and functioning level of the learner

• Establish a series of steps between the initial value and the terminal value– 8-12 steps are recommended– Increase 33% to 50% at each step

• Stay at one step at least 2 times• If student is unsuccessful, go back a step• Periodically probe a few steps ahead

LeBlanc et al.: Thinning from FR1

1 FR2 100%

2 FR4 100%

3 FR6 50%

4 FR9 50%

5 FR12 33%

6 FR16 33%

7 FR21 33%

8 FR28 33%

Differential Reinforcement of Rates of Responding

• DRH: Reinforcement of responses higher than a predetermined criterion (to produce a higher rate of responding)

• DRL: Reinforcement of responses lower than a predetermined criterion (to produce a lower rate of responding)

• 3 Types– Spaced-responding: reinforcement is only available for responses

separated by a given duration of time (IRT)• Not used much b/c it’s difficult to calculate IRT

– Full session: reinforcement is delivered at the end of the session if the total number of responses during the session was less than or more than a criterion

– Interval: Total session is divided into equal intervals and reinforcement is delivered at the end of each interval in which the number of responses was less than or more than a criterion

Compound Schedules of Reinforcement

• Combine different types of schedules

• Concurrent Schedules

• Discriminative Schedules– Multiple Schedules– Chained Schedules

• Nondiscriminative Schedules– Mixed Schedules– Tandem Schedules

Concurrent Schedules

• 2 or more contingencies of reinforcement operate independently and at the same time for 2 or more behaviors

• Used for– Reinforcer Assessments– Intervention Assessments

• Hanley et al. (2005) allowed individuals to choose which intervention they preferred

– FCT + Punishment was preferred to FCT + Extinction

– Interventions• Hoch et al. (2002) – boys with autism could play alone or with sibling

– Sibling was chosen when SR magnitude and quality were increased

• Use this when you can’t or shouldn’t treat inappropriate behavior directly

Multiple Schedule

• A type of discriminative schedule

• Two or more schedules are presented one after another

– Each is correlated with a discriminative stimulus

• Tiger and Hanley (2004)– Different colored leis worn by the teacher were SDs

correlated with schedules of reinforcement for attention

FR1 Component (SD)

EXT Component (S∆)

0

20

40

60

80

10 20 30 40 50 60 70

Sessions

Freq

uenc

y of

Man

dsFR 1 Mult FR 1 / EXT FR 1

Delay to Sr

Sr

Delay to Sr

EXT

Minimum response criterion

15 s – 270 s 5s–1s 1 s – 60 s

Chained Schedule

• A type of discriminative schedule

• Differs from multiple schedule:– Schedules in the chain occur in the same order– Behavior may be the same or different for each component

of the chain– Conditioned reinforcement for the first element of the chain

is presentation of the second element• The last response is reinforced with most powerful reinforcer

Nondiscriminative Schedules

• Mixed (like multiple schedule without the SDs)– Tiger and Hanley (2004) – conducted the

same sessions without the teacher wearing leis

• Tandem (like chained with out the SDs)

Use Caution…

• When extrapolating information about schedules from basic research to applied settings– Most applications of schedules only approximate

lab schedules– Many uncontrolled variables in applied settings will

influence a person’s sensitivity and insensitivity to a schedule of reinforcement