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Chapter 12
The Similarities Between
Operant Conditioning and
Natural Selection
Sources of Behavioral Variation
• In evolution by natural selection, the 2 principle
sources of variation are 1) Genetic Mutations
and 2) Recombinations of Genes during Sexual
Reproduction
– The expressions of these new genetic forms in both
structures and behaviors provide the raw materials
for natural selection
• There are two main sources of behavioral
variation:
• 1) Induced Variation
• 2) Behavioral Variability
Induced Variation
• Refers to behaviors generated by the situation
• The particular behaviors that are induced
depend on the species of the individual, his or
her motivational state and past history, and the
attributes of the situation
• Behaviors can be induced by internal events such
as the depletion of nutrients or external events
such as the presence of food, water, mates, etc.
• Variation in behavior can also be induced by the
withholding or reduction in the level of reward
– Not giving a reward causes the individual to engage in different
behaviors until they receive the reward again
• Therefore, by manipulating the situation you can
induce different responses from individuals
Behavioral Variability
• Even in an unchanging environment, individuals
do not perform actions exactly the same way
every time they have the opportunity to
perform them
• Every day each one of us experiences this.
• For example, it is rare that each time you brush
your teeth you apply the same exact amount of
toothpaste and brush each tooth the same
exact way every morning and night
• There are usually some differences even if very
small that occur each time you perform the
same behavior
Function of Behavioral Variation
in Operant Conditioning
• Induced Variation = produces patterns of
behavior that have been useful to the subject
in the same or similar situation in obtaining
reinforcement
• Once the subject comes to perform the correct
action, Behavioral Variability in that
performance increases the chances that more
efficient versions of the action will be selected
through the process of hill-climbing
Selection in Operant Conditioning
• The selection in natural selection refers to the
mechanism for determining who will survive long
enough to reproduce (A mechanism called
Reproductive Fitness)
• In Operant Conditioning, selection of successful
behaviors depends on their consequences
– (Note: Providing a consequence does not automatically
produce selection of the behavior that produced that
consequence because some behaviors are harder to
learn than other and require experiencing more than a
single consequence)
• There are 2 main mechanisms of selection:
1) Temporal Proximity
2) The Behavior-Consequence Contingency
What 2 Theorists Identified Temporal
Proximity as a Mechanism of Selection?
1) Thorndike
•
•
Believed that temporal proximity b/w a behavior and
reinforcer was the mechanism for selection and that it was
both a necessary & sufficient condition for the selection of
behavior
But he was wrong
2) Skinner
•
•
Believed that temporal proximity was mechanism for selection
based on a finding that noncontingent presentations of food
appeared to select certain behavior, which he called
“Superstitious Behaviors”
He was also wrong; the behaviors he observed were not the
result of selection by termporal proximity; they were induced
by the periodic presentation of food
So, is temporal proximity really
a mechanism for selection?
• Temporal proximity is mechanism for
selection, but it is neither a necessary
nor sufficient condition for the
occurrence of operant conditioning
• Therefore, it cannot be the only
mechanism of selection
• That leaves the behavior-consequence
contingency as the remaining candidate
Why do people perform
superstitious rituals?
• Superstitions are causal inferences based on the chance
conjunctions of events
• Temporal proximity aids in the development of causal
inferences but it is not a necessary condition
• Superstitious behavior in humans is more likely to be
due to RULE-GOVERNED BEHAVIOR (rules that guide
our behavior and make us less sensitive to the
contingencies of reinforcement)
• So if you believe that walking under a ladder brings you
bad luck, even though nothing bad happens when you
actually do walk under a ladder, because you have that
“rule” in your head, you won’t walk under the ladder
• Thus, it doesn’t matter if you are reinforced or not, you
still won’t do it
The Behavior-Consequence
Contingency
• Is this the only mechanism for selection?
– NO
– Because the mere presence of a contingency
does not guarantee that a behavior will be
selected by that contingency
– Thus, the Behavior-Consequence Contingency
is also neither a necessary nor a sufficient
condition for the occurrence of operant
conditioning
What does Selection Actually
Involve?
• It involves a combination of both
temporal proximity and behaviorconsequence contingency
• The individual uses both of the methods
to test whether the reinforcing event is
sue to chance or is in fact brought on by
his or her behavior
Does selection involve gradual molding
of behavior or the creation of new
behavioral programs?
• Shaping behavior by the method of successive
approximations and the procedure of
differentiation suggest that operant
conditioning involves gradual molding of
behavior by their consequences – This is NOT
correct
• Operant conditioning creates new behavioral
programs which involves the rearrangement of
existing behavior modules
Are selected behaviors
strengthened or retained?
• The use of the word reiforcement or
reinforcer in operant conditioning
suggests that behaviors are strengthened
by their consequences, but in natural
selection, traits are retained (not
strengthened) by selection
• We cannot distinguish between these 2
possibilities with our current level of
knowledge
Operant Conditioning as an
Adaptive Specialization
• The mechanisms underlying instrumental
learning and operant conditioning evolved
so that individuals can use the
consequences of their actions to discover
what works and does not work in order to
become more efficient in the future