Download Chapter 6 (Learning).

Chapter 6
Phobias: Irrational fears of specific objects or situations, often the result of a type of learning called
classical conditioning
Learning: A relatively durable change in behaviour or knowledge due to experience - includes the
acquisition of knowledge and skills, but also habits, personality traits, emotional responses, and
preferences
Much study on learning is performed with animals, as much more control can be exerted over them
Conditioning: A type of learning where associations are made between events occurring in an organism's
environment
Classical Conditioning (p. 239)
Classical conditioning (Pavlovian conditioning): A type of learning where a stimulus acquires the capacity
to evoke a response that was originally evoked by another stimulus - for example, a dog starting to drool
any time a can opener is used, because it's usually followed by food
Ivan Pavlov was trying to study the digestive system of dogs when he discovered classical conditioning he was measuring the saliva they produced when eating, yet after a while they began to salivate before
the food was given
He began giving various cues that food was on the way, such as ringing a bell - eventually the bell, a
neutral stimulus, would be enough to make the dog salivate
Thus, the tone acquired the capacity to trigger the same response originally reserved for food
Terminology
Unconditioned stimulus: A stimulus that evokes an unconditioned response without previous
conditioning
Unconditioned response: An unlearned reaction to an unconditioned stimulus that occurs without
previous conditioning
Conditioned stimulus: A previously neutral stimulus that has, through conditioning, acquired the capacity
to evoke a conditioned response
Conditioned response: A learned reaction to a conditioned stimulus that occurs because of previous
conditioning
The unconditioned response and conditioned response consist of basically the same behaviour salivating, for example
Conditioned responses have been characterized as reflexes because they are automatic or involuntary the responses themselves are said to be elicited or drawn forth
Trial: Any presentation of a stimulus or pair of stimuli - the key measurement in classical conditioning
being how many trials are required to establish a bond
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Pavlov's classical conditioning
Classical conditioning in everyday life
Classical conditioning often plays a key role in shaping emotional responses such as fears and phobias for example, a child tormented by her father as they cross a rickety bridge may become afraid of all
bridges
Positive things can also elicit emotional responses - for example, a particular song may be related to
events in your life, or people may be more tempted to buy a product endorsed b a famous or attractive
person
Classical conditioning may also be related to the development of fetishes
Classical conditioning and drugs
Classical conditioning also contributes to drug tolerance and withdrawal symptoms - the body produces
compensatory responses to counteract the effects of the drug on the body
Compensatory conditioned responses: Adaptive attempts made by the body to compensate for the
effects of drugs - most drugs users have routines that lead to the pairing of drugs with certain stimuli,
which begin to elicit compensatory responses to cancel out the effects of the drugs
If the drugs are taken in a new way or setting, the compensatory effects won't occur - vastly increasing
the risk of overdose
Processes in classical conditioning
Most conditioned responses are reflexive and difficult to control - you can't really stop yourself from
salivating or being afraid
Acquisition: The initial stage of learning something
Stimulus contiguity: When stimuli are paired together in time and space - the optimal delay is 0.5
seconds
Not all pairings produce classical conditioning, despite the many stimuli we experience - stimuli
that are novel, unusual or especially intense have more potential to become conditioned stimuli,
because they stand out
Extinction: The gradual weakening and disappearance of a conditioned response - the consistent
presentation of the conditioned stimulus alone, without the unconditioned stimulus, will reduce the
capacity for the conditioned stimulus to elicit the response
The strength of the conditioned bond affects the number of trials required for extinction - some
extinguish quickly, while others are difficult to weaken
Spontaneous recovery: The reappearance of an extinguished response after a period of nonexposure to
the conditioned stimulus
Pavlov's dogs, after having more or less stopped responding to the conditioned stimulus, would
then salivate again the next day when presented with it - though less than they had before
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then salivate again the next day when presented with it - though less than they had before
If the conditioned stimulus was presented alone again, the response would re-extinguish quickly
Renewal effect: If a response is extinguished in a different environment from where it was
acquired, it will reappear if returned to the original environment - this suggests that extinction
doesn't lead to erasing the learned association
Even if you manage to rid yourself of a conditioned response, it may make an unexpected
recovery
Stimulus generalization: When an organism has learned a response to a specific stimulus, and responds
in the same way to similar stimuli
For example, being afraid of all dogs after having been bit by a single dog - a potentially adaptive
response
The likelihood of generalization depends on the similarity between the new stimulus and the
original conditioned stimulus - the more similar new stimuli are, the greater the generalization
Generalization gradients: Graphs of the strength of generalization response
Stimulus discrimination: When an organism does not respond in the same way to a stimulus similar to
one it has been conditioned to
Organisms can gradually learn to discriminate between the original conditioned stimulus and
similar stimuli if they have experience with both
Development of stimulus discrimination requires the original conditioned stimulus being paired
with the unconditioned stimulus, while similar stimuli are not paired with the unconditioned
stimulus
The less similar stimuli are, the greater the likelihood and ease of discrimination - if they are quite
similar, discrimination will be difficult to learn
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similar, discrimination will be difficult to learn
Higher-order conditioning: When a conditioned stimulus functions as if were an unconditioned
stimulus - the response is internalized to the point of seeming natural
Also shows that classical conditioning doesn't depend on a genuine unconditioned stimulus - new
conditioned responses can be built on top of already established conditioned responses
Operant Conditioning (p. 247)
Operant conditioning (instrumental learning): A form of learning in which responses come to be
controlled by their consequences - this regulates voluntary responses and involves stimuli that occur
after the response
Edward Thorndike emphasized that this type of conditioning is often instrumental in obtaining an
outcome - i.e. it seems to cause the outcome - which led to his Law of Effect
Law of effect: If a response in the presence of a stimulus leads to satisfying effects, the association
between the stimulus and response is strengthened
B.F. Skinner demonstrated that organisms tend to repeat responses that are followed by favourable
consequences
Reinforcement: When an event followed by a response increases an organism's tendency to make that
response
Operant chamber (Skinner Box): A small enclosure in which an animal can make a specific response that
is recorded while the consequences are systematically controlled - an automated system for testing
conditioning
Operant responses are voluntary, and so they are said to be emitted
Reinforcement contingencies: The circumstances or rules that determine whether responses lead to the
presentation of reinforcers - the experimenter manipulates whether positive consequences occur when
the animal makes the designated response
Response rate: The key variable measured in operant conditioning - represents the learning that is
occurring, as an animal will respond more often as a stronger connection is made
Cumulative recorder: A part of the Skinner Box that creates a graphic record of responding and
reinforcement as a function of time - when there is no responding, a horizontal line is drawn, and when
the designated response occurs it moves upward - a steep line reproduces a quick response rate
Processes in operant conditioning
Shaping: Reinforcement of closer and closer approximations of a desired response - for example, reward
a rat every time it gets progressively closer to a lever it is supposed to press
Shaping is necessary when an organism doesn't naturally emit the desired response - rats don't
generally press levers on their own
Extinction: The gradual weakening and disappearance of a response tendency because it is no longer
followed by a reinforcer - a brief surge in response rate occurs at first, then a gradual decline
Resistance to extinction: When an organism continues to make a response after delivery of the
reinforcer has been terminated - the greater the resistance to extinction, the longer responding will
continue
Discriminative stimuli: Cues that influence operant behaviour by indicating the probably consequences
(reinforcement or not) of a response
When a response is consistently followed by a reinforcer in the presence of a particular stimulus
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When a response is consistently followed by a reinforcer in the presence of a particular stimulus
(food is delivered when a green light is on) the stimulus comes to serve as a signal indicating that
the reinforcer is coming - a rat will learn to only press a lever when the green light comes on
Generalization would occur if your pet responded to the sound of a new kitchen appliance
(thinking it is the can opener) while discrimination would be learning to only respond to the can
opener
Reinforcement
Reinforcement occurs whenever an outcome strengthens a response (measured by an increase in the
rate of responding) - this is defined after the fact
For example, wearing a particular shirt on the day you do well on a test could lead to a
superstitious behaviour of wearing that shirt any day you have a big test - this would be
reinforcement of a response
Primary reinforcers: Events that are inherently reinforcing because they satisfy biological needs - food,
water, warmth, sex, etc.
Secondary reinforcers: Events that acquire reinforcing qualities by being associated with primary
reinforcers - these vary among members of a species because they depend on learning, but some
common examples for humans would be money, good grades, attention, or applause
Schedules of reinforcement
Schedule of reinforcement: Determines which occurrences of a specific response result in the
presentation of a reinforcer
Continuous reinforcement: When every instance of a designated response is reinforced - i.e. food is
given every time a rat presses a lever - this is used to shape and establish a new response
Intermittent (partial) reinforcement: When a designated response is reinforced only some of the time
Given an equal number of reinforcements, intermittent reinforcement makes a response more
resistant to extinction
Types of intermittent reinforcement:
Fixed-ratio schedule: The reinforcer is given after a fixed number of nonreinforced responses - i.e. food
is given every 10th time a rat presses a lever
Variable-ratio schedule: The reinforcer is given after a variable number of nonreinforced responses
around a set average - i.e. food is given roughly every tenth time a rat presses a lever, though it may
occur on the 8th or the 12th
Fixed-interval schedule: The reinforcer is given for the first response that occurs after a specific time
interval has passed - i.e. food is given when a rat presses a lever ten minutes after the last press
Variable-interval schedule: The reinforcer is given for the first response after a variable time interval has
passed, varying around a set average - i.e. food is given when a rat presses a lever roughly ten minutes
after the last press
Ratio schedules tend to produce more rapid responding, because faster rates lead to sooner
reinforcement, and variable schedules generate steadier response rate and greater resistance to
extinction - gambling, which is reinforced by a variable-ratio schedule, produces rapid and steady
responding
Negative reinforcement
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Negative reinforcement
Positive reinforcement: Occurs when a response is strengthened because it is followed by the
presentation of a rewarding stimulus
Negative reinforcement: When a response is strengthened because it is followed by the removal of an
aversive stimulus - note that it is still reinforcement, as the response rate is strengthened
For example, positive reinforcement rewards a rat with food when it presses a lever - negative
reinforcement is turning off an electrical shock when the rat presses a lever
Escape learning: When an organism acquires a response that decreases or ends some aversive stimulus
Avoidance learning: When an organism acquires a response that prevents an aversive stimulus from
occurring
For example, initially a rat will run to another compartment of a Skinner box only when a light comes on
and it is shocked - eventually, it will start running to the other compartment as soon as it notices a light
coming on
Initially, avoidance learning is reflexive, conditioned fear - fleeing to the other part of the box is operant
behaviour caused by negative reinforcement
Phobias are a good example of avoidance learning - they're never given the opportunity to extinguish
because you're never exposed to the conditioned stimulus
Punishment
Punishment: When an event following a response weakens the tendency to make that response punishment typically involves presenting an aversive stimulus or removal rewarding stimuli
Positive punishment: Application of aversive consequences
Negative punishment: Removal of a reward
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This produces the opposite effect of negative reinforcement - negative reinforcement is removing an
aversive stimulus (not nagging your kid after he takes out the garbage - strengthening the response)
while punishment is adding an aversive stimulus (taking away your kid's cell phone if he doesn't take out
the garbage - weakening the response)
Primary punisher: Something inherently punishing - such as an electric shock, spanking, yelling
Secondary punisher: A stimulus with punishing properties through association with a primary punisher
Effectively giving punishments involves several steps:
- Apply punishment swiftly - A delay undermines its impact
- Use punishment just severe enough to be effective - Severe punishments are more effective in
weakening the response, but they also increase the likelihood of negative side effects
- Make punishment consistent - Punish the response every time
- Explain the punishment - Explain the reason for punishment as fully as possible - if they
understand why they were punished, the punishment will be more effective
- Use noncorporal punishment - Noncorporal punishments are a more prudent means to achieve
disciplinary goals, as they have less likelihood for negative side effects
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disciplinary goals, as they have less likelihood for negative side effects
Changing Directions in the Study of Conditioning (p. 261)
Biological effects on conditioning
There are limits to the generality of conditioning imposed by biology - some are easier to learn, while
others are nearly impossible
Instinctive drift: When an animal's innate response tendencies interfere with the conditioning process for instance, giving food to raccoons when they picked up coins led them to obsessively rub the coins
together as though washing food
Conditioned taste aversion: Many people develop aversions to food that is followed by nausea normally, delays of more than 30 seconds makes association difficult, yet nausea experienced hours
later can result in conditioning
- When followed by other types of noxious stimuli, taste aversions are not developed - it only
happens with nausea
- This seems to be an evolutionary trait to teach us what not to eat
Preparedness: A species-specific predisposition to be conditioned in certain ways, and not others - for
example, most common phobias (snakes, spiders, heights) were once threats to survival
Taste aversion learning is not that unique - it's just an ecologically relevant conditioned stimulus, which
gives much greater effects than the traditionally arbitrary, neutral stimuli
- In the real world, conditioned stimuli have natural relationships to the unconditioned stimuli they
predict - a heavy focus on arbitrary cues may have created a skewed view of conditioning
Cognitive effects on conditioning
Signal relations: The relationship between a conditioned stimulus and an unconditioned stimulus namely, whether the conditioned stimulus allows accurate prediction of the unconditioned stimulus
Predictive value: The likelihood an unconditioned stimulus will follow a conditioned stimulus - for
example, if a shock is only sent half the time after a tone is played, then its predictive value is 50%
Response-outcome relations: The logical relationship between a stimulus and response - reinforcement
is not automatic, rather it happens when it seems that the response caused the stimulus
Organisms actively try to figure out the contingencies (what leads to what) in the world around them good signals are used to minimize aversive experiences and maximize pleasant experiences
Observational Learning (p. 265)
Observational learning: Occurs when an organism's responding is influenced by the observation of
others, called models
Both classical and operant conditioning can occur through observational learning - essentially,
observational learning is being conditioned indirectly by observing another's conditioning
Basic process
Attention: You must pay attention to another person's behaviour and its consequences
Retention: You have to store the observed response in your mind, so that you can replicate it in the
future
Reproduction: You enact the modelled response by converting your stored mental images into overt
behaviour
Motivation: You have to encounter a situation where you believe the response you observed will pay off
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behaviour
Motivation: You have to encounter a situation where you believe the response you observed will pay off
for you
Acquisition vs performance
Reinforcements affect which response are performed, rather than those which are acquired - people
emit the responses they think will be reinforced, but acquire many that they never end up performing
Mirror neurons: Neurons that are activated by performing an action or by seeing another perform the
same action - located in the frontal lobe and parietal lobe in humans
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