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
Contingency
Every R Sr
No Rs  Sr
Some Rs  Sr
Schedule
Continuous Sr (CRF)
Extinction (EXT)
Intermittent Sr (INT)
Probability of Sr
p =1.0
p=0
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
Ratio
(# of Rs)
Interval
(Time since last reinforced R)
Fixed
(Requirement
for Sr constant)
FIXED RATIO (FR)
Sr delivered following
fixed # of Rs
FIXED INTERVAL (FI)
Sr delivered following 1st R
after fixed amt time since
last reinforced R
Variable
(Requirement
for Sr changes)
VARIABLE RATIO (VR) VARIABLE INTERVAL (VR)
Sr delivered following
Sr delivered following 1st R
# Rs that varies around
after variable amt time since
an average value
last reinforced R
Schedule Effects on Behavior
Ratio
(High R rate)
Fixed
(Irregular R rate)
FIXED RATIO (FR)
High, irregular rate
(“Break and run”)
Variable
(Stable R rate)
VARIABLE RATIO (FR)
High stable rate
Interval
(Moderate R rate)
FIXED INTERVAL (FI)
Moderate irregular rate
(“FI scallop”)
VARIABLE INTERVAL (VI)
Moderate stable rate
Response Patterns Generated by Basic Schedules
40
CUMULATIVE # OF RESPONSES
VR: High stable rate
FIXED RATIO
30
VARIABLE RATIO
FR: High irregular rate
FIXED INTERVAL
VARIABLE INTERVAL
20
VI: Moderate stable rate
FI: Moderate irregular rate
10
0
0
10
20
30
40
SESSON TIME
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)
50
VR signaled via bell and light
Points exchanged for backup Sr+ (based on survey)
Social Validity: Satisfaction, physical activity, appearance (Ss, patents, teachers)
Results
Participant
Scott (N)
Shawn (N)
Steve (N)
Peter (O)
Paul (O)
Perry (O)
BL
Stable
∆∆Stable
Stable
Stable
VR#1
∆++
∆++
∆++
∆++
∆++
∆++
VR#2
∆+
∆+
∆+
∆+
∆+
∆+
VR#3
∆+
∆++
∆+
∆++
∆+
∆+
BL
∆∆∆∆∆∆-
VR#3
∆++
∆++
∆+
∆++
∆++
∆+
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