Classical conditioning (also known as Pavlovian or respondent conditioning) is learning through association and was discovered by Pavlov, a Russian physiologist. In simple terms, two stimuli are linked together to produce a new learned response in a person or animal.
John Watson proposed that the process of classical conditioning (based on Pavlov’s observations) was able to explain all aspects of human psychology.
If you pair a neutral stimulus (NS) with an unconditioned stimulus (US) that already triggers an unconditioned response (UR) that neutral stimulus will become a conditioned stimulus (CS), triggering a conditioned response (CR) similar to the original unconditioned response.
Everything from speech to emotional responses was simply patterns of stimulus and response. Watson completely denied the existence of the mind or consciousness. Watson believed that all individual differences in behavior were due to different learning experiences.
Watson (1924, p. 104) famously said:
Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select – doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations and the race of his ancestors.
How Classical Conditioning Works
There are three stages of classical conditioning. At each stage, the stimuli and responses are given special scientific terms:
Stage 1: Before Conditioning:
In this stage, the unconditioned stimulus (UCS) produces an unconditioned response (UCR) in an organism.
In basic terms, this means that a stimulus in the environment has produced a behavior/response that is unlearned (i.e., unconditioned) and, therefore, is a natural response that has not been taught. In this respect, no new behavior has been learned yet.
For example, a stomach virus (UCS) would produce a response of nausea (UCR). In another example, a perfume (UCS) could create a response of happiness or desire (UCR).
This stage also involves another stimulus that has no effect on a person and is called the neutral stimulus (NS). The NS could be a person, object, place, etc.
The neutral stimulus in classical conditioning does not produce a response until it is paired with the unconditioned stimulus.
Stage 2: During Conditioning:
During this stage, a stimulus which produces no response (i.e., neutral) is associated with the unconditioned stimulus, at which point it now becomes known as the conditioned stimulus (CS).
For example, a stomach virus (UCS) might be associated with eating a certain food such as chocolate (CS). Also, perfume (UCS) might be associated with a specific person (CS).
For classical conditioning to be effective, the conditioned stimulus should occur before the unconditioned stimulus, rather than after it, or during the same time. Thus, the conditioned stimulus acts as a type of signal or cue for the unconditioned stimulus.
In some cases, conditioning may take place if the NS occurs after the UCS (backward conditioning), but this normally disappears quite quickly. The most important aspect of the conditioning stimulus is the it helps the organism predict the coming of the unconditional stimulus.
Often during this stage, the UCS must be associated with the CS on a number of occasions, or trials, for learning to take place.
However, one trial learning can happen on certain occasions when it is not necessary for an association to be strengthened over time (such as being sick after food poisoning or drinking too much alcohol).
Stage 3: After Conditioning:
The conditioned stimulus (CS) has been associated with the unconditioned stimulus (UCS) to create a new conditioned response (CR).
For example, a person (CS) who has been associated with nice perfume (UCS) is now found attractive (CR). Also, chocolate (CS) which was eaten before a person was sick with a virus (UCS) now produces a response of nausea (CR).
Classical Conditioning Examples
Pavlov’s Dogs
The most famous example of classical conditioning was Ivan Pavlov’s experiment with dogs, who salivated in response to a bell tone. Pavlov showed that when a bell was sounded each time the dog was fed, the dog learned to associate the sound with the presentation of the food.
He first presented the dogs with the sound of a bell; they did not salivate so this was a neutral stimulus. Then he presented them with food, they salivated. The food was an unconditioned stimulus, and salivation was an unconditioned (innate) response.
He then repeatedly presented the dogs with the sound of the bell first and then the food (pairing) after a few repetitions, the dogs salivated when they heard the sound of the bell. The bell had become the conditioned stimulus and salivation had become the conditioned response.
Fear Response
Watson & Rayner (1920) were the first psychologists to apply the principles of classical conditioning to human behavior by looking at how this learning process may explain the development of phobias.
They did this in what is now considered to be one of the most ethically dubious experiments ever conducted – the case of Little Albert. Albert B.’s mother was a wet nurse in a children’s hospital. Albert was described as ‘healthy from birth’ and ‘on the whole stolid and unemotional’.
When he was about nine months old, his reactions to various stimuli (including a white rat, burning newspapers, and a hammer striking a four-foot steel bar just behind his head) were tested.
Only the last of these frightened him, so this was designated the unconditioned stimulus (UCS) and fear the unconditioned response (UCR). The other stimuli were neutral because they did not produce fear.
When Albert was just over eleven months old, the rat and the UCS were presented together: as Albert reached out to stroke the animal, Watson struck the bar behind his head.
This occurred seven times in total over the next seven weeks. By this time, the rat, the conditioned stimulus (CS), on its own frightened Albert, and fear was now a conditioned response (CR).
The CR transferred spontaneously to the rabbit, the dog, and other stimuli that had been previously neutral. Five days after conditioning, the CR produced by the rat persisted. After ten days, it was ‘much less marked’, but it was still evident a month later.
Carter and Tiffany (1999) support the cue reactivity theory, they carried out a meta-analysis reviewing 41 cue-reactivity studies that compared responses of alcoholics, cigarette smokers, cocaine addicts and heroin addicts to drug-related versus neutral stimuli.
They found that dependent individuals reacted strongly to the cues presented and reported craving and physiological arousal.
Panic Disorder
Classical conditioning is thought to play an important role in the development of Pavlov (Bouton et al., 2002).
Panic disorder often begins after an initial “conditioning episode” involving an early panic attack. The panic attack serves as an unconditioned stimulus (US) that gets paired with neutral stimuli (conditioned stimuli or CS), allowing those stimuli to later trigger anxiety and panic reactions (conditioned responses or CRs).
The panic attack US can become associated with interoceptive cues (like increased heart rate) as well as external situational cues that are present during the attack. This allows those cues to later elicit anxiety and possibly panic (CRs).
Through this conditioning process, anxiety becomes focused on the possibility of having another panic attack. This anticipatory anxiety (a CR) is seen as a key step in the development of panic disorder, as it leads to heightened vigilance and sensitivity to bodily cues that can trigger future attacks.
The presence of conditioned anxiety can serve to potentiate or exacerbate future panic attacks. Anxiety cues essentially lower the threshold for panic. This helps explain how panic disorder can spiral after the initial conditioning episode.
Evidence suggests most patients with panic disorder recall an initial panic attack or conditioning event that preceded the disorder. Prospective studies also show conditioned anxiety and panic reactions can develop after an initial panic episode.
Classical conditioning processes are believed to often occur outside of conscious awareness in panic disorder, reflecting the operation of emotional neural systems separate from declarative knowledge systems.
Addiction
Cue reactivity is the theory that people associate situations (e.g., meeting with friends)/ places (e.g., pub) with the rewarding effects of nicotine, and these cues can trigger a feeling of craving (Carter & Tiffany, 1999).
These factors become smoking-related cues. Prolonged use of nicotine creates an association between these factors and smoking based on classical conditioning.
Nicotine is the unconditioned stimulus (UCS), and the pleasure caused by the sudden increase in dopamine levels is the unconditioned response (UCR). Following this increase, the brain tries to lower the dopamine back to a normal level.
The stimuli that have become associated with nicotine were neutral stimuli (NS) before “learning” took place but they became conditioned stimuli (CS), with repeated pairings. They can produce the conditioned response (CR).
However, if the brain has not received nicotine, the levels of dopamine drop, and the individual experiences withdrawal symptoms therefore is more likely to feel the need to smoke in the presence of the cues that have become associated with the use of nicotine.
Classroom Learning
The implications of classical conditioning in the classroom are less important than those of operant conditioning, but there is still a need for teachers to try to make sure that students associate positive emotional experiences with learning.
If a student associates negative emotional experiences with school, then this can obviously have bad results, such as creating a school phobia.
For example, if a student is bullied at school they may learn to associate the school with fear. It could also explain why some students show a particular dislike of certain subjects that continue throughout their academic career. This could happen if a student is humiliated or punished in class by a teacher.
Principles of Classical Conditioning
Neutral Stimulus
In classical conditioning, a neutral stimulus (NS) is a stimulus that initially does not evoke a response until it is paired with the unconditioned stimulus.
For example, in Pavlov’s experiment, the bell was the neutral stimulus, and only produced a response when paired with food.
Unconditioned Stimulus
Unconditioned Response
In classical conditioning, an unconditioned response is an innate response that occurs automatically when the unconditioned stimulus is presented.
Pavlov showed the existence of the unconditioned response by presenting a dog with a bowl of food and measuring its salivary secretions.
Conditioned Stimulus
Conditioned Response
In classical conditioning, the conditioned response (CR) is the learned response to the previously neutral stimulus.
In Ivan Pavlov’s experiments in classical conditioning, the dog’s salivation was the conditioned response to the sound of a bell.
Acquisition
The process of pairing a neutral stimulus with an unconditioned stimulus to produce a conditioned response.
In the initial learning period, acquisition describes when an organism learns to connect a neutral stimulus and an unconditioned stimulus.
Extinction
In psychology, extinction refers to the gradual weakening of a conditioned response by breaking the association between the conditioned and the unconditioned stimuli.
The weakening of a conditioned response occurs when the conditioned stimulus is repeatedly presented without the unconditioned stimulus.
For example, when the bell repeatedly rang, and no food was presented, Pavlov’s dog gradually stopped salivating at the sound of the bell.
Spontaneous Recovery
Spontaneous recovery is a phenomenon of Pavlovian conditioning that refers to the return of a conditioned response (in a weaker form) after a period of time following extinction.
It is the reappearance of an extinguished conditioned response after a rest period when the conditioned stimulus is presented alone.
For example, when Pavlov waited a few days after extinguishing the conditioned response, and then rang the bell once more, the dog salivated again.
Generalization
In psychology, generalization is the tendency to respond in the same way to stimuli similar (but not identical) to the original conditioned stimulus.
For example, in Pavlov’s experiment, if a dog is conditioned to salivate to the sound of a bell, it may later salivate to a higher-pitched bell.
Discrimination
In classical conditioning, discrimination is a process through which individuals learn to differentiate among similar stimuli and respond appropriately to each one.
For example, eventually, Pavlov’s dog learns the difference between the sound of the 2 bells and no longer salivates at the sound of the non-food bell.
Higher-Order Conditioning
Higher-order conditioning is when a conditioned stimulus is paired with a new neutral stimulus to create a second conditioned stimulus. For example, a bell (CS1) is paired with food (UCS) so that the bell elicits salivation (CR). Then, a light (NS) is paired with the bell.
Eventually, the light alone will elicit salivation, even without the presence of food. This demonstrates higher-order conditioning, where the conditioned stimulus (bell) serves as an unconditioned stimulus to condition a new stimulus (light).
Critical Evaluation
Strengths
Practical applications
The principles of classical conditioning have been widely and effectively applied in fields like behavioral therapy, education, and advertising. Therapies like systematic desensitization use classical conditioning to help eliminate phobias and anxiety.
The behaviorist approach has been used in the treatment of phobias, and systematic desensitization. The individual with the phobia is taught relaxation techniques and then makes a hierarchy of fear from the least frightening to the most frightening features of the phobic object.
He then is presented with the stimuli in that order and learns to associate (classical conditioning) the stimuli with a relaxation response. This is counter-conditioning.
Explaining involuntary behaviors
Classical conditioning helps explain some reflexive or involuntary behaviors like phobias, emotional reactions, and physiological responses. The model shows how these can be acquired through experience.
The process of classical conditioning can probably account for aspects of certain other mental disorders. For example, in post-traumatic stress disorder (PTSD), sufferers tend to show classically conditioned responses to stimuli present at the time of the traumatizing event (Charney et al., 1993).
However, since not everyone exposed to the traumatic event develops PTSD, other factors must be involved, such as individual differences in people’s appraisal of events as stressors and the recovery environment, such as family and support groups.
Supported by substantial experimental evidence
There is a wealth of experimental support for basic phenomena like acquisition, extinction, generalization, and discrimination. Pavlov’s original experiments on dogs and subsequent studies have demonstrated classical conditioning in animals and humans.
There have been many laboratory demonstrations of human participants acquiring behavior through classical conditioning. It is relatively easy to classically condition and extinguish conditioned responses, such as the eye-blink and galvanic skin responses.
A strength of classical conditioning theory is that it is scientific. This is because it’s based on empirical evidence carried out by controlled experiments. For example, Pavlov (1902) showed how classical conditioning could be used to make a dog salivate to the sound of a bell.
Supporters of a reductionist approach say that it is scientific. Breaking complicated behaviors down into small parts means that they can be scientifically tested. However, some would argue that the reductionist view lacks validity. Thus, while reductionism is useful, it can lead to incomplete explanations.
Weaknesses
Ignores biological predispositions
Organisms are biologically prepared to associate certain stimuli over others. However, classical conditioning does not sufficiently account for innate predispositions and biases.
Classical conditioning emphasizes the importance of learning from the environment, and supports nurture over nature.
However, it is limiting to describe behavior solely in terms of either nature or nurture, and attempts to do this underestimate the complexity of human behavior. It is more likely that behavior is due to an interaction between nature (biology) and nurture (environment).
Lacks explanatory power
Classical conditioning provides limited insight into the cognitive processes underlying the associations it describes.
However, applying classical conditioning to our understanding of higher mental functions, such as memory, thinking, reasoning, or problem-solving, has proved more problematic.
Even behavior therapy, one of the more successful applications of conditioning principles to human behavior, has given way to cognitive–behavior therapy (Mackintosh, 1995).
Questionable ecological validity
While lab studies support classical conditioning, some question how well it holds up in natural settings. There is debate about how automatic and inevitable classical conditioning is outside the lab.
In normal adults, the conditioning process can be overridden by instructions: simply telling participants that the unconditioned stimulus will not occur causes an instant loss of the conditioned response, which would otherwise extinguish only slowly (Davey, 1983).
Most participants in an experiment are aware of the experimenter’s contingencies (the relationship between stimuli and responses) and, in the absence of such awareness often fail to show evidence of conditioning (Brewer, 1974).
Evidence indicates that for humans to exhibit classical conditioning, they need to be consciously aware of the connection between the conditioned stimulus (CS) and the unconditioned stimulus (US). This contradicts traditional theories that humans have two separate learning systems – one conscious and one unconscious – that allow conditioning to occur without conscious awareness (Lovibond & Shanks, 2002).
There are also important differences between very young children or those with severe learning difficulties and older children and adults regarding their behavior in a variety of operant conditioning and discrimination learning experiments.
These seem largely attributable to language development (Dugdale & Lowe, 1990). This suggests that people have rather more efficient, language-based forms of learning at their disposal than just the laborious formation of associations between a conditioned stimulus and an unconditioned stimulus.
Ethical concerns
The principles of classical conditioning raise ethical concerns about manipulating behavior without consent. This is especially true in advertising and politics.
- Manipulation of preferences – Classical conditioning can create positive associations with certain brands, products, or political candidates. This can manipulate preferences outside of a person’s rational thought process.
- Encouraging impulsive behaviors – Conditioning techniques may encourage behaviors like impulsive shopping, unhealthy eating, or risky financial choices by forging positive associations with these behaviors.
- Preying on vulnerabilities – Advertisers or political campaigns may exploit conditioning techniques to target and influence vulnerable demographic groups like youth, seniors, or those with mental health conditions.
- Reduction of human agency – At an extreme, the use of classical conditioning techniques reduces human beings to automata reacting predictably to stimuli. This is ethically problematic.
Deterministic theory
A final criticism of classical conditioning theory is that it is deterministic. This means it does not allow the individual any degree of free will. Accordingly, a person has no control over the reactions they have learned from classical conditioning, such as a phobia.
The deterministic approach also has important implications for psychology as a science. Scientists are interested in discovering laws that can be used to predict events.
However, by creating general laws of behavior, deterministic psychology underestimates the uniqueness of human beings and their freedom to choose their destiny.
The Role of Nature in Classical Conditioning
Behaviorists argue all learning is driven by experience, not nature. Classical conditioning exemplifies environmental influence. However, our evolutionary history predisposes us to learn some associations more readily than others. So nature also plays a role.
Example 1
For example, PTSD develops in part due to strong conditioning during traumatic events. The emotions experienced during trauma lead to neural activity in the amygdala, creating strong associative learning between conditioned and unconditioned stimuli (Milad et al., 2009).
Individuals with PTSD show enhanced fear conditioning, reflected in greater amygdala reactivity to conditioned threat cues compared to trauma-exposed controls. In addition to strong initial conditioning, PTSD patients exhibit slower extinction to conditioned fear stimuli.
During extinction recall tests, PTSD patients fail to show differential skin conductance responses to extinguished versus non-extinguished cues, indicating impaired retention of fear extinction. Deficient extinction retention corresponds to reduced activation in the ventromedial prefrontal cortex and hippocampus and heightened dorsal anterior cingulate cortex response during extinction recall in PTSD patients.
Example 2
In influential research on food conditioning, John Garcia found that rats easily learned to associate a taste with nausea from drugs, even if illness occurred hours later.
However, conditioning nausea to a sight or sound was much harder. This showed that conditioning does not occur equally for any stimulus pairing. Rather, evolution prepares organisms to learn some associations that aid survival more easily, like linking smells to illness.
Example 3
The evolutionary significance of taste and nutrition ensures robust and resilient classical conditioning of flavor preferences, making them difficult to reverse (Hall, 2002).
Forming strong and lasting associations between flavors and nutrition aids survival by promoting the consumption of calorie-rich foods. This makes flavor conditioning very robust.
Repeated flavor-nutrition pairings in these studies lead to overlearning of the association, making it more resistant to extinction.
The learning is overtrained, context-specific, and subject to recovery effects that maintain the conditioned behavior despite extinction training.
Classical vs. operant condioning
In summary, classical conditioning is about passive stimulus-response associations, while operant conditioning is about actively connecting behaviors to consequences. Classical works on reflexes and operant on voluntary actions.
- Stimuli vs consequences: Classical conditioning focuses on associating two stimuli together. For example, pairing a bell (neutral stimulus) with food (reflex-eliciting stimulus) creates a conditioned response of salivation to the bell. Operant conditioning is about connecting behaviors with the consequences that follow. If a behavior is reinforced, it will increase. If it’s punished, it will decrease.
- Passive vs. active: In classical conditioning, the organism is passive and automatically responds to the conditioned stimulus. Operant conditioning requires the organism to perform a behavior that then gets reinforced or punished actively. The organism operates on the environment.
- Involuntary vs. voluntary: Classical conditioning works with involuntary, reflexive responses like salivation, blinking, etc. Operant conditioning shapes voluntary behaviors that are controlled by the organism, like pressing a lever.
- Association vs. reinforcement: Classical conditioning relies on associating stimuli in order to create a conditioned response. Operant conditioning depends on using reinforcement and punishment to increase or decrease voluntary behaviors.
Learning Check
- In Ivan Pavlov’s famous experiment, he rang a bell before presenting food powder to dogs. Eventually, the dogs salivated at the mere sound of the bell. Identify the neutral stimulus, unconditioned stimulus, unconditioned response, conditioned stimulus, and conditioned response in Pavlov’s experiment.
- A student loves going out for pizza and beer with friends on Fridays after class. Whenever one friend texts the group about Friday plans, the student immediately feels happy and excited. The friend starts texting the group on Thursdays when she wants the student to feel happier. Explain how this is an example of classical conditioning. Identify the UCS, UCR, CS, and CR.
- A college student is traumatized after a car accident. She now feels fear every time she gets into a car. How could extinction be used to eliminate this acquired fear?
- A professor always slams their book on the lectern right before giving a pop quiz. Students now feel anxiety whenever they hear the book slam. Is this classical conditioning? If so, identify the NS, UCS, UCR, CS, and CR.
- Contrast classical conditioning and operant conditioning. How are they similar and different? Provide an original example of each type of conditioning.
- How could the principles of classical conditioning be applied to help students overcome test anxiety?
- Explain how taste aversion learning is an adaptive form of classical conditioning. Provide an original example.
- What is second-order conditioning? Give an example and identify the stimuli and responses.
- What is the role of extinction in classical conditioning? How could extinction be used in cognitive behavioral therapy for anxiety disorders?
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