Schedules of Reinforcement
Definition:
A formula (or rule) describing the probability that a given R will produce reinforcement; or, a formula describing the proportion of Rs that will be reinforced
Schedules are based on a continuum of probability values
ContingencyScheduleProbability of Sr
Every R Sr Continuous Sr (CRF) p =1.0
No Rs Sr Extinction (EXT)p = 0
Some Rs Sr Intermittent Sr (INT)0 < p < 1.0
Advantages of Intermittent Reinforcement
Prevents satiation: INT Sr maintains state of deprivation (EO)
Resistance to EXT: INT is less predictable than CRF; therefore; change to EXT more difficult to discriminate
Can produce high rates of R (more Rs required for Sr)
Naturalistic: Most schedules in natural environment are INT
Cost effective: Easier for agent to administer
Basic Schedule Parameters
Response requirement:
Ratio: Sr based on number of Rs
Interval: Sr based on time elapsed since last reinforced R
Regularity:
Fixed: Requirement constant between Sr deliveries
Variable: Requirement changes from one Sr delivery to another
Basic Schedules of Reinforcement
RatioInterval
(# of Rs)(Time since last reinforced R)
FixedFIXED RATIO (FR)FIXED INTERVAL (FI)
(Requirement Sr delivered followingSr delivered following 1st R
for Sr constant)fixed # of Rsafter fixed amt time since
last reinforced R
VariableVARIABLE RATIO (VR)VARIABLE INTERVAL (VR)
(RequirementSr delivered following Sr delivered following 1st R
for Sr changes)# Rs that varies aroundafter variable amt time since
an average valuelast reinforced R
Schedule Effects on Behavior
RatioInterval
(High R rate)(Moderate R rate)
FixedFIXED RATIO (FR)FIXED INTERVAL (FI)
(Irregular R rate)High, irregular rateModerate irregular rate
(“Break and run”)(“FI scallop”)
VariableVARIABLE RATIO (FR)VARIABLE INTERVAL (VI)
(Stable R rate)High stable rateModerate stable rate
Response Patterns Generated by Basic Schedules
DeLuca & Holborn (1992)
General Focus:
Application of behavioral principles to the treatment of childhood obesity
Specific Aims:
To increase rates of exercise
To determine whether VR schedules are more effective than FR and FI schedules
To use a changing criterion design to shape gradual increases in behavior
Procedures
Experimental Designs:
Changing Criterion (BL + 3 VR phases)
Reversal: A-B1-B2-B3-A-B3
Conditions:
Baseline: No special instructions or contingencies
Reinforcement (VR):
VR point schedule (+15% BL or previous phase)
VR signaled via bell and light
Points exchanged for backup Sr+ (based on survey)
Social Validity: Satisfaction, physical activity, appearance (Ss, patents, teachers)
Results
ParticipantBLVR#1VR#2VR#3BLVR#3
Scott (N)Stable∆++∆+∆+∆-∆++
Shawn (N)∆-∆++∆+∆++∆-∆++
Steve (N)∆-∆++∆+∆+∆-∆+
Peter (O)Stable∆++∆+∆++∆-∆++
Paul (O)Stable∆++∆+∆+∆-∆++
Perry (O)Stable∆++∆+∆+∆-∆+
Implications and Extensions
Major contribution: Interesting application of Sr schedules and changing criterion design as shaping procedure for increasing exercise behavior
Limitations:
Was performance under VR better than under FR or FI?
Were criterion increases necessary?
Other indices of improvement?
Extensions:
IV: Schedule questions unanswered
DV: Additional measures of benefit
DV: Other forms of exercise (convenience)
DV: Other behaviors related to obesity
Population or setting