Learning and Adaptation: The Role of Experience
Learning: is a process by which experience produces a relatively enduring change in an
organism’s behaviour or capabilities (process of personal adaptation to the ever-changing
circumstances of our lives).
Capabilities: highlights a distinction made by many theorists: “knowing how”, or
leaning, versus “doing”, or performance.
Habituation and sensitization: involve a change in behaviour that results from repeated
exposure to a single stimulus.
Classical conditioning: occurs when two stimuli become associated wit each other.
Operant conditioning: we learn to associate our responses with specific consequences.
Observational learning: we learn by watching others behave.
Adapting To The Environment
How Do We Learn? The Search For Mechanisms
• Interaction with immediate and past environment.
• The cognitive perspective, biological factors, and cross-cultural psychology have
expanded our understanding of learning.
Habituation and Sensitization
Habituation: is the decrease in the strength of response to a repeated stimulus.
• Key adaptive function
• E.g. You do not need to constantly respond to the stimulus of your clothing
• Learning not to respond to uneventful familiar stimuli (conserve energy)
• Simple form of learning that occurs in the central nervous system
• Sensory information is still available if it become relevant
Sensitization: increase in the strength of response to a repeated stimulus.
• Each time the stimulus reoccurs it elicits a stronger response
• Tends to occur to strong or noxious stimuli
• Its purpose is to increase responses to a potentially dangerous stimulus
Classical Conditioning: Associating One Stimulus With Another
Classical conditioning: an organism learns to associate two stimuli, such that one
stimulus comes to produce a response that originally was produced only by other
• Learning an association between stimuli Pavlov’s Pioneering Research
• Discovered that with repeated testing, dogs began to salivate before the food was
presented, such as when they heard the footsteps of the approaching experimenter.
• Dogs have a natural reflex to salivate to food but not to tones. Yet when a tone or
other stimulus that ordinarily did not cause salivation was presented just before
food powder was squirted directly into a dog’s mouth, the sound of the tone alone
soon made the dog salivate (classical conditioning).
• Classical conditioning alerts organisms to stimuli that signal the impending arrival
of an important event.
• If salivation could be continued, so might other bodily processes?
• Acquisition: refers to the period during which a response is being learned.
• Neutral stimulus: does not elicit the salivation response.
• Unconditioned stimulus (UCS): a stimulus that elicits a particular reflexive or
innate response without prior learning.
• Unconditioned response (UCR): a response that is elicited by a specific stimulus
without prior learning.
• Conditioned stimulus (CS): a neutral stimulus that comes to evoke a conditioned
response after being paired with an unconditioned stimulus.
• Conditioned response (CR): in classical conditioning, a response to a
conditioned stimulus; the CR is established by pairing a conditioned stimulus with
an unconditioned stimulus that evokes a similar response.
• Classical conditioning usually is strongest when there are repeated CS-USC
pairings, the UCS is more intense, the sequence involves forward pairing, and the
time interval between the CS and UCS is short.
Extinction and Spontaneous Recovery
Extinction: If the CS is presented repeatedly in the absence of the UCS, the CR weakens
and eventually disappears.
• Extinction trial: each presentation of the CS without the UCS
• Not all traces of it are erased
Spontaneous recovery: the reappearance of a previously extinguished CR after a rest
period and without new learning trials.
• Recovered CR is usually weaker than initial CR, and extinguishes more rapidly in
the absence of UCS.
Generalization and Discrimination
• Organisms respond not only the original CS, but also to stimuli similar to it.
Stimulus generalization: stimuli similar to the initial SC elicit a CR.
• Serves as a critical adaptive function
Discrimination: a CR occurs to one stimulus (a sound), but not to others. Higher-Order Conditioning
Higher-order conditioning: A neutral stimulus becomes a CS after being paired with an
already established CS.
• Produces a CR that is weaker and extinguishes more rapidly than the original CR
Applications of Classical Conditioning
Acquiring and Overcoming Fear
• If phobias are learned, they can be “unlearned”
• Exposure therapies: basic goasl is to expose the phobic patient to the feared
stimulus (CS) without any UCS, allowing the extinction to occur.
• Systematic desensitization: patients learn muscular relaxation techniques and
then they are gradually exposed to the fear-provoking stimulus.
• Flooding: immediately exposes the person to the phobic stimulus.
Conditioned Attraction and Aversion
• Originally neutral stimuli can trigger sexual arousal after they have been paired
with a naturally arousing USC.
• Aversion therapy: condition an aversion (repulsion) to a stimulus that triggers
unwanted behaviour by pairing it with a noxious UCS.
• Neutral stimuli acquire favourable of unfavourable meaning by being paired with
other stimuli that already elicit positive or negative attitudes.
• We seem to be biologically prepared to easily learn to fear stimuli such as heights,
snakes, spiders, and bats.
• It is relatively easy to condition an aversion to a taste by pairing a taste and an
illness, but it is very difficult to condition a similar aversion to a visual stimulus
by pairing a visual cue and an illness.
• When a neutral stimulus is repeatedly paired with a natural allergen (the UCS), it
may become a CS that triggers an allergic CR.
Operant Conditioning: Learning Through Consequences
• Not elicit responses automatically triggered by some stimulant, but they are
emitted (voluntary) responses.
Thorndike’s Law of Effect
• Puzzle box, that could be opened from the inside by pulling a string or stepping
on a lever.
• With trial-and-error, they gradually eliminated responses that failed to open the
door, and became more likely to perform actions that worked (instrumental
• Law of effect: stated that in a given situation, a response followed by a
“satisfying” consequence will become more likely to occur, and a response
followed by an unsatisfying outcome will become less likely to occur. Skinner’s Analysis of Operant Conditioning
Operant behaviour: an organism operates on its environment in some way; it emits
responses that produce certain consequences.
Operant conditioning: is a type of learning in which behaviour is influenced by its
• Responses that produce favourable consequences tend to be repeated
• Responses that produce unfavourable consequences become less likely to occur
• Viewed operant conditioning as a type of “natural selection” that facilitates an
organism’s personal adaptation to the environment (increase behaviours that
benefit them, and reduce behaviours that harm them).
• Skinner box: special chamber to study operant conditioning experimentally (a
lever on the wall drops a food pellet into a small cup)
Two important types of consequences:
1. Reinforcement: a response is strengthened by an outcome that follows it. The
outcome that increases the frequency of a response is called a reinforcer.
2. Punishment: occurs when a response is weakened by outcomes that follow it.
Punisher is a consequence that weakens the behaviour.
ABCs of Operant Conditioning
Three (3) kinds of events
1. Antecedents (A): stimuli that are present before behaviour occurs
2. Behaviours (B): that the organism emits
3. Consequences (C): that follow the behaviour
*If antecedent stimuli are present, AND behaviour is emitted, THEN consequences will
Contingencies: The relations between A and B, and between B and C
Key differences between classical and operant conditioning
• In classical conditioning, the organism learns an association between two stimuli-
the CS and UCS-that occurs before the behaviour. In operant conditioning, the
organism learns an association between behaviour and its consequences.
Behaviour changes because of events that occur after it.
• Classical conditioning focuses on elicited behaviours. The conditioned response is
triggered involuntarily, almost like a reflex, by a stimulus that precedes it.
Operant conditioning focuses on emitted behaviours: In a given situation, the
organism generates responses that are under physical control.
Antecedent Conditions: Identifying When To Respond
Discriminative stimulus: a signal that a particular response will now produce certain
consequences. They “set the occasion” for operant responses.
Consequences: Determining How To Respond Positive Reinforcement
Positive reinforcement: A response is strengthened by a subsequent presentation of a
stimulus. The stimulus that follows and strengthens the response is called a positive
Negative reinforcement: A response is strengthened by the subsequent removal or
avoidance of a stimulus. The stimulus that is removed or avoided is called a negative
• Not to be confused with punishment (Reinforcement always means that a
response is being strengthened, whereas punishment weakens a response)
Operant extinction: is the weakening and eventual disappearance of a response because
it is no longer reinforced.
• The degree to which non-reinforced responses persist is called resistance to
o Strongly influenced by the pattern of reinforcement that has previously
maintained the behaviour.
• Operant extinction often provides a good alternative to punishment as a method
for reducing undesirable behaviour.
Positive punishment or aversive punishment: occurs when a response is weakened by
the subsequent presentation of a stimulus (aversive stimuli: painful slaps, electric shock,
• Produces rapid results
• Suppresses the behaviour but does not cause the organism to forget how to make
the response (e.g. children refrain from using bad language only when their
parents are around)
• Punishment arouses negative emotion (fear, anger), which can produce dislike of
the person delivering the punishment
• Amounts to control by aggression (send the message that aggression is
Negative punishment: a response weakened by the subsequent removal of a stimulus
Two distinct advantages over positive punishment:
1. It is less likely to create strong fear or even hatred of the punishing agent
2. Punishing agent is not modelling physical aggression through imitation
Primary and Secondary Consequences
Primary reinforcers: are stimuli, such as food and water, that an organism naturally
finds reinforcing because they satisfy biological needs. Secondary (conditioned) reinforcers: a stimulus that acquires reinforcing qualities by
being associated with a primary reinforcer (e.g. money).
• Illustrates how behaviour often depends on a combination of classical and operant
• A primary consequence has its value because of biological importance. A
secondary consequence has its importance because of learning.
Immediate versus Delayed Consequences
• Immediate punishment has stronger effects than delayed punishment
Delay of gratification: the ability to forego an immediate smaller reward for a delayed
but more satisfying outcome.
• Young children who display less ability to delay gratification show poorer
adjustment and have more difficulty coping with stress and frustration when they
• May play a role in behaviour such as chronic drinking, smoking, and even
• Immediate gratifying consequences override the delayed benefits of not
performing the behaviour.
Shaping and Chaining: Taking One Step At A Time
Shaping: reinforcing successive approximations toward a final response (method of
Chaining: is used to develop a sequence (chain) of responses by reinforcing each
response with the opportunity to perform the next response.
• Chaining usually beings with the final response in the sequence and works
backwards toward the first response.
Generalization and Discrimination
• Operant responses may generalize to similar antecedent situations
Operant generalization: an operant response occurs to a new antecedent stimulus or
situation that is similar to the original one.
Operant discrimination: means that an operant response will occur to one antecedent
stimulus (parents’ presence or absence) but not to another.
• When antecedent stimuli influence behaviour, that behaviour is said to be under
• Operant discrimination training: teach an organism that making a response when
a discriminative stimulus is present produces food or some other positive
consequence. Schedules of Reinforcement
Continuous reinforcement schedule: every response of a particular type is reinforced.
Partial reinforcement: only some responses are reinforced.
1. Ratio versus interval schedules
• Ratio schedules
o A certain percentage of responses is reinforced
• Interval schedules
o A certain amount of time must elapse between reinforcements, regardless
of how many correct responses might occur during