Theories of Reinforcement
n  Skinner’s
n  Two
Basic Theory Types
n  Hull’s
n  The
View
Drive Reduction Theory
Premack Principle
n  Response
n  Bliss
Deprivation Theory
Point Theory
Skinner’s view of Reinforcement
n
No theory required
n
An empirical issue
n  If something acts to increase a B, then it’s a SR
n
Inductive viewpoint
n  A SR is a stimulus that reinforces the operant R
Two Types of Theories
n
Reinforcers as Stimuli (Hull)
n
Reinforcers as Activities
_________
SR = Eating the food
n  SR = Food
_______
n  SR = TV
SR = Watching TV
n  Three
Main “Reinforcers as Activities” Theories
Hull’s Drive-Reduction Theory
(A Reinforcers-as-Stimuli theory)
n
Stimuli that reduce a biological need, or that reduce
strong aversive stimulation, will become reinforcers
DRIVE
n
ACT
DRIVE REDUCED (Pos. SR)
Hunger à Lever press à Receive food (SR)
DRIVE REDUCED
(Neg. SR)
Escape shock pain à Lever press à Shock ends (SR)
DRIVE
n
ACT
Hull’s Drive-Reduction Theory cont.
n
Three types of reinforcement:
n
Primary Reinforcers
n  Stimuli that reduce drives (food)
n  Stimuli that result in the reduction of another
strong aversive stimulus (painkillers)
n
Secondary Reinforcers
n  Stimuli associated with drive-reducing stimuli
(kitchen, cooking shows, meetings w/ snacks)
A Problem with Hull’s Theory
Researchers found stimuli that had high reinforcement
value, yet did NOT reduce any drives:
n
Monkeys pulled chains to see lab and its workers
n
Rats lever pressed to stimulate pleasure centers
Premack’s Principle
n
Reinforcement is a Contingency between two Bs
n
“Instrumental R;” “Contingent R”
n
Getting to do the second B is CONTINGENT upon
first performing the INSTRUMENTAL B
n
Doing the first B is INSTRUMENTAL in your being
able to perform the second (CONTINGENT) B
n
Can consider Contingent activity as the Reinforcer
Premack’s Principle cont.
n
Not all behaviors are reinforcers!
n
More probable Bs reinforce less probable Bs
n
Contingent B should have higher probability than
the Instrumental B
n
n
Instrumental B (↓ prob.) à Contingent B (↑
prob.)
How to measure these probabilities?
n  Free Baseline (aka Paired Baseline)
Premack’s Principle cont.
The Bottom Line:
n
Getting to perform the More probable B is
CONTINGENT upon performing the Less probable,
INSTRUMENTAL B
n
To demonstrate a significant Contingency Effect,
you MUST perform the Instrumental B ABOVE
baseline level!
Shortfalls of Premack’s Principle
n
Premack assumed that the more preferred activities
were those that people spent more time doing during
baseline
n
Doing homework: 30 minutes - multiple hours
n
Having sex: ? min./hours (typically < homework)
Shortfalls of Premack’s Principle cont.
n
Premack did NOT attach time amts. to his Bs
n
Free baseline: Run 60 min., Drink 30 min.
n
Contingency: Drink 15 min. à Run 30 min.
n
Result – Rat drank 30 min., then ran 60 min.
n
No increase above baseline => No contingency effect
Response-Deprivation Theory
(Timberlake & Allison)
n
n
A Reinforcement Effect will occur ONLY when the
reinforcement contingency deprives the S of the
contingent activity
n
Performing baseline amt. of Instrumental R earns
you less than baseline amount of Contingent R
n
Make S perform Instrumental B at a higher level than
its baseline to obtain at least the baseline level of the
Contingent B
Can↑ time req’d for BI, or↓ time allowed for BC
Response-Deprivation Theory cont.
n
n
Premack: Behavior probabilities;
Response Deprivation : Behavior preferences
contingent activity doesn’t have to be more probable
n
ANY activity can be reinforcing, as long as the
subject is deprived of performing it at baseline
Response-Deprivation cont.
n
Use less-preferred activity as Instrumental B to gain
access to the more-preferred Contingent B
n  Employ these in ratios that are above baseline
n
Subjects do not always perform contingencies as
predicted/calculated by Response-Deprivation
n
Subjects instead alter their behaviors to compromise
Bliss Point Theory (Allison)
n
Baseline = behavioral ideal
n
Behavioral ideal drives performance
n
Any contingency imposed disrupts bliss point
n
S increases frequency of BI as a compromise
n
Point of Minimum Deviation
n  Accurately predicted by formulae