in pavlov's dog experiment what was the unconditioned response

Classical Conditioning: How It Works With Examples

Saul McLeod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

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Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

On This Page:

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 B. 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.

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.

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

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.

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.

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.

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.

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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Pavlov’s Dog: The Psychology Experiment That Changed Everything

Pavlov’s Dog is a well-known experiment in psychology that has been taught for decades. Ivan Pavlov , a Russian physiologist, discovered classical conditioning through his experiments with dogs. He found that dogs could be trained to associate a sound with food, causing them to salivate at the sound alone.

The experiment began with Pavlov ringing a bell every time he fed his dogs. After a while, the dogs began to associate the sound of the bell with food and would salivate at the sound alone, even if no food was present. This became known as a conditioned response, where a previously neutral stimulus (the bell) became associated with a natural response (salivating).

The experiment has been used to explain many psychological phenomena, including addiction, phobias, and anxiety. It has also been applied in therapy, where patients can learn to associate positive experiences with previously negative stimuli. The Pavlov’s Dog experiment is a crucial part of psychology’s history and continues to be studied today.

Pavlov’s Life and Career

Ivan Pavlov was a Russian physiologist who lived from 1849 to 1936. He is best known for his work in classical conditioning, a type of learning that occurs when a neutral stimulus is consistently paired with a stimulus that elicits a response. Pavlov was born in Ryazan, Russia, and studied at the University of St. Petersburg, where he received his doctorate in 1879.

Pavlov’s early research focused on the digestive system, and he discovered that the secretion of gastric juice was not a passive process but rather a response to stimuli. This led him to develop the concept of the conditioned reflex, which he explored in detail in his famous experiments with dogs.

In these experiments, Pavlov trained dogs to associate the sound of a bell with food presentation. Over time, the dogs began to salivate at the sound of the bell, even when no food was present. This demonstrated that a neutral stimulus (the bell) could become associated with a natural response (salivation) through repeated pairings with a stimulus that elicits that response (food).

Pavlov’s work had a profound impact on the field of psychology, and his ideas continue to influence research today. He was awarded the Nobel Prize in Physiology or Medicine in 1904 for his work on the physiology of digestion. Still, his legacy is best remembered for his contributions to the study of learning and behavior.

Classical Conditioning

Classical conditioning is a type of learning that occurs when a neutral stimulus is repeatedly paired with a stimulus that naturally elicits a response. Over time, the neutral stimulus becomes associated with the natural stimulus and begins to produce the same response. Russian physiologist Ivan Pavlov first studied this type of learning in the late 1800s.

One of the most famous examples of classical conditioning is Pavlov’s experiment with dogs. In this experiment, Pavlov rang a bell every time he fed the dogs. Eventually, the dogs began to salivate at the sound of the bell, even when no food was present. The sound of the bell had become associated with the food, and the dogs had learned to associate the two stimuli.

Classical conditioning can be used to explain a variety of behaviors and responses. For example, a person who has been in a car accident may develop a fear of driving. The sound of screeching tires or the sight of a car may become associated with the traumatic experience, causing the person to feel anxious or fearful when driving.

Classical conditioning can also be used to treat certain types of phobias and anxiety disorders. By gradually exposing a person to the feared stimulus in a safe and controlled environment, the person can learn to associate the stimulus with safety and relaxation rather than fear and anxiety.

Classical conditioning is a powerful tool for understanding how we learn and respond to environmental stimuli. By understanding the principles of classical conditioning, we can better understand our behaviors and emotions, as well as those of others around us.

Pavlov’s Experiments

Pavlov’s experiments with dogs revolutionized the field of psychology and laid the foundation for the study of classical conditioning. In this section, we will explore two aspects of his experiments: salivating dogs and conditioned responses.

Salivating Dogs

Pavlov observed that dogs would salivate when presented with food. However, he also noticed that the dogs would start salivating before the food was presented. This led him to hypothesize that the dogs were responding not just to the food but to other associated stimuli, such as the sound of the food being prepared or the sight of the person who fed them.

To test his hypothesis, Pavlov began a series of experiments where he would ring a bell before presenting the dogs with food. After a few repetitions, the dogs began to salivate at the sound of the bell alone, even when no food was present. This demonstrated that the dogs had learned to associate the sound of the bell with the presence of food and were responding accordingly.

Conditioned Response

Pavlov’s experiments with dogs led to the discovery of the conditioned response, the learned response to a previously neutral stimulus. In the case of Pavlov’s dogs, the sound of the bell was originally a neutral stimulus. Still, it became associated with food and, therefore, elicited a response (salivation) from the dogs.

The conditioned response is an essential concept in psychology, as it helps to explain how we learn to respond to various stimuli in our environment. For example, if we have a positive experience with a particular food, we may develop a conditioned response to the sight or smell of that food, even if we are not hungry.

Pavlov’s experiments with dogs were groundbreaking in psychology and led to the discovery of classical conditioning and the conditioned response. By demonstrating that animals (and humans) can learn to respond to previously neutral stimuli, Pavlov paved the way for further research into the mechanisms of learning and behavior.

Significance in Psychology

Pavlov’s dog experiment has been a significant discovery in psychology. It has paved the way for developing various theories and has been instrumental in understanding human behavior. In this section, we will discuss the significance of Pavlov’s dog experiment in the context of behaviorism and learning theories.

Behaviorism

Pavlov’s dog experiment has been a cornerstone in the development of behaviorism. Behaviorism is a school of thought in psychology that emphasizes the importance of observable behavior rather than internal mental states. Pavlov’s experiment demonstrated how a stimulus-response connection could be formed through conditioning. This concept has been used to explain various behaviors, such as phobias and addictions.

Learning Theories

Pavlov’s dog experiment has also been significant in developing learning theories . Learning theories are concerned with how people acquire new knowledge and skills. Pavlov’s experiment demonstrated how classical conditioning could teach animals new behaviors. This concept has been used to explain various learning phenomena, such as the acquisition of language and the development of social skills.

In conclusion, Pavlov’s dog experiment has been a significant discovery in psychology. It has been instrumental in the development of behaviorism and learning theories. By understanding the principles of classical conditioning, we can better understand human behavior and how we learn new skills and behaviors.

Implications in Modern Psychology

Pavlov’s dog experiments have had a significant impact on modern psychology. His theory of classical conditioning has become a cornerstone of behaviorism, a school of thought that dominated psychology in the early 20th century. Today, it continues to influence psychologists and researchers in various fields.

One of the most significant implications of Pavlov’s work is the understanding of how learning takes place. His experiments showed that animals, including humans, can learn through association. This concept has been applied in many areas of modern psychology, including education, advertising, and even politics.

For example, in education, classical conditioning can improve students’ learning by associating positive experiences with specific subjects or activities. In advertising, classical conditioning can create positive associations between a product and a particular emotion or experience, influencing consumers’ purchasing decisions.

Moreover, Pavlov’s work has also contributed to developing other learning theories, such as operant conditioning, which focuses on the consequences of behavior rather than the stimuli that precede it. These theories have been used to explain various human behaviors, from addiction to language acquisition.

Pavlov’s dog experiments have had a lasting impact on modern psychology. His theory of classical conditioning has contributed to our understanding of how learning takes place and has been applied in various fields, from education to advertising. His work has also influenced the development of other learning theories, making it a crucial part of studying human behavior.

Criticism and Controversies

While Pavlov’s experiments have been foundational in psychology, they have also been subject to criticism and controversy. Here are a few examples:

• Animal cruelty:  Some critics argue that Pavlov’s experiments on dogs were cruel and unethical. The dogs were often subjected to painful surgeries and kept in small cages for long periods. While these practices were common in the early 20th century, they would not be acceptable by today’s ethical standards.
• Oversimplification of behavior:  Pavlov’s experiments focused on classical conditioning, which suggests that behavior is determined solely by external stimuli. However, this oversimplifies the complex nature of human behavior, which is influenced by various factors, including genetics, environment, and personal experience.
• Limited generalizability:  Pavlov’s experiments were conducted on dogs, which may not accurately reflect human behavior. While some of the principles of classical conditioning may apply to humans, it is essential to recognize that there are also significant differences between species.
• Misinterpretation of results:  Pavlov’s work has been subject to misinterpretation over the years. For example, many people believe that Pavlov’s dogs learned to salivate at the sound of a bell because they associated it with food. However, this is only partially accurate. The dogs learned to associate the sound of the bell with the experimenter’s presence, who would then provide the food.

Frequently Asked Questions

What were the basic features of classical conditioning discovered by pavlov.

Classical conditioning is a type of learning in which a neutral stimulus becomes associated with a meaningful stimulus, resulting in a behavioral response. Pavlov discovered that when a neutral stimulus (such as a bell) was repeatedly paired with a meaningful stimulus (such as food), the neutral stimulus alone could elicit the same response (such as salivation) as the meaningful stimulus.

What was the purpose of Pavlov’s dog experiment?

Pavlov’s dog experiment was designed to study the process of classical conditioning. He wanted to understand how dogs learn to associate a neutral stimulus (such as a bell) with a meaningful stimulus (such as food) and how this association leads to a behavioral response (such as salivation).

How did Pavlov’s experiments contribute to the development of psychology?

Pavlov’s experiments were groundbreaking in the field of psychology. They provided evidence for the concept of classical conditioning, which has since been used to explain a wide range of human and animal behaviors. Pavlov’s work also paved the way for the development of behaviorism, a school of psychology that emphasizes the importance of observable behavior in understanding human and animal psychology.

What is the Pavlovian response and how does it work?

The Pavlovian response is a learned response to a previously neutral stimulus. It works by pairing the neutral stimulus with a meaningful stimulus, which leads to the formation of an association between the two. Once the association is formed, the neutral stimulus alone can elicit the same response as the meaningful stimulus.

How is Pavlovian conditioning used in dog training?

Pavlovian conditioning is often used in dog training to teach dogs new behaviors or to modify existing ones. For example, a trainer might use a clicker (a neutral stimulus) to signal to a dog that it has performed a desired behavior (a meaningful stimulus), and then reward the dog with a treat. Over time, the dog will learn to associate the clicker with the reward and will perform the desired behavior without the need for a treat.

What is the Pavlovian response in humans and how is it studied?

The Pavlovian response in humans is similar to that in dogs: it involves the formation of an association between a neutral stimulus and a meaningful stimulus, resulting in a learned response. This response has been studied in a variety of contexts, including addiction, phobias, and taste aversions. Researchers use a variety of methods to study the Pavlovian response in humans, including brain imaging techniques and behavioral experiments.

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Classical Conditioning

Affiliations.

• 1 Cornell University
• 2 A.T. Still University
• 3 Touro University, Nevada
• 4 University Hospital Lewisham
• PMID: 29262194
• Bookshelf ID: NBK470326

Learning is the process through which individuals acquire new knowledge, behaviors, attitudes, and ideas. Humans must be sensitive to both meaningful and coincidental relationships between events in the environment to survive. This learning process happens through both unconscious and conscious pathways. Classical conditioning, also known as associative learning, is an unconscious process where an automatic, conditioned response becomes associated with a specific stimulus. Although Edwin Twitmyer published findings on classical conditioning a year before Ivan Pavlov, the most recognized work in the field is attributed to Pavlov (a Russian physiologist born in the mid-1800s). Pavlov's significant contributions to classical conditioning have led to the term "Pavlovian conditioning" being used to describe it.

The discovery of classical conditioning was accidental. While researching the digestion of dogs, Pavlov observed that the dogs' physical responses to food gradually changed. Initially, the dogs only salivated when the food was directly presented. However, he later noticed that the dogs began to salivate slightly before the food arrived in response to sounds consistently associated with feeding, such as the sound of the food cart. To test his theory, Pavlov conducted an experiment where he rang a bell shortly before presenting food to the dogs. Initially, the dogs did not salivate in response to the bell. However, as they learned to associate the sound of the bell with the arrival of food, they began to salivate at the sound alone.

An unconditioned stimulus is something that naturally triggers an automatic response. In Pavlov's experiment, the food acted as the unconditioned stimulus. The unconditioned response is the automatic reaction to that stimulus, which in this case was the dogs salivating in response to the food.

A neutral stimulus initially elicits no response. Pavlov introduced the ringing of the bell as a neutral stimulus. Over time, a neutral stimulus can become a conditioned stimulus, which eventually triggers a conditioned response. In Pavlov's experiment, the ringing of the bell became the conditioned stimulus, and salivation was the conditioned response. Essentially, the neutral stimulus transforms into the conditioned stimulus. While the unconditioned and conditioned responses are the same physiological reaction—salivation—the difference lies in the stimulus that elicits them. In Pavlov's experiments, salivation was the response. The unconditioned response, triggered by food, was salivation, while the bell triggered the conditioned response.

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What Is Classical Conditioning in Psychology?

How It Works, Terms to Know, and Examples

Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital.

• Definitions
• How It Works

Key Principles of Classical Conditioning in Psychology

What is the difference between classical conditioning and operant conditioning, frequently asked questions.

Discovered by Russian physiologist Ivan Pavlov , classical conditioning is a type of unconscious or automatic learning. This learning process creates a conditioned response through associations between an unconditioned stimulus and a neutral stimulus. In simple terms, classical conditioning involves placing a neutral stimulus before a naturally occurring reflex.

One of the best-known examples of classical conditioning is Pavlov's classic experiments with dogs. In these experiments, the neutral signal was the sound of a tone and the naturally occurring reflex was salivating in response to food. By associating the neutral stimulus (sound) with the unconditioned stimulus (food), the sound of the tone alone could produce a salivation response.

Although classical conditioning was not discovered by a psychologist, it has had a tremendous influence over the school of thought in psychology known as behaviorism . Behaviorism assumes that all learning occurs through interactions with the environment and that environment shapes behavior.

Classical Conditioning Definitions

Classical conditioning—also sometimes referred to as Pavlovian conditioning—uses a few different terms to help explain the learning process. Knowing these basics will help you understand classical conditioning.

Unconditioned Stimulus

An unconditioned stimulus is a stimulus or trigger that leads to an automatic response. If a cold breeze makes you shiver, for instance, the cold breeze is an unconditioned stimulus; it produces an involuntary response (the shivering).

Neutral Stimulus

A neutral stimulus is a stimulus that doesn't initially trigger a response on its own. If you hear the sound of a fan but don't feel the breeze, for example, it wouldn't necessarily trigger a response. That would make it a neutral stimulus.

Conditioned Stimulus

A conditioned stimulus is a stimulus that was once neutral (didn't trigger a response) but now leads to a response. If you previously didn't pay attention to dogs, but then got bit by one, and now you feel fear every time you see a dog, the dog has become a conditioned stimulus.

Unconditioned Response

An unconditioned response is an automatic response or a response that occurs without thought when an unconditioned stimulus is present. If you smell your favorite food and your mouth starts watering, the watering is an unconditioned response.

Conditioned Response

A conditioned response is a learned response or a response that is created where no response existed before. Going back to the example of being bit by a dog, the fear you experience after the bite is a conditioned response.

Click Play to Learn More About Classical Conditioning

This video has been medically reviewed by Ann-Louise T. Lockhart, PsyD, ABPP .

How Classical Conditioning Works

Classical conditioning involves forming an association between two stimuli, resulting in a learned response. There are three basic phases of this process.

Phase 1: Before Conditioning

The first part of the classical conditioning process requires a naturally occurring stimulus that will automatically elicit a response. Salivating in response to the smell of food is a good example of a naturally occurring stimulus.

During this phase of the process, the unconditioned stimulus (UCS) results in an unconditioned response (UCR). Presenting food (the UCS) naturally and automatically triggers a salivation response (the UCR).

At this point, there is also a neutral stimulus that produces no effect—yet. It isn't until the neutral stimulus is paired with the UCS that it will come to evoke a response.

Let's take a closer look at the two critical components of this phase of classical conditioning:

• The unconditioned stimulus is one that unconditionally, naturally, and automatically triggers a response. For example, when you smell one of your favorite foods, you may immediately feel hungry. In this example, the smell of the food is the unconditioned stimulus.
• The unconditioned response is the unlearned response that occurs naturally in response to the unconditioned stimulus. In our example, the feeling of hunger in response to the smell of food is the unconditioned response.

In the before conditioning phase, an unconditioned stimulus is paired with an unconditioned response. A neutral stimulus is then introduced.

Phase 2: During Conditioning

During the second phase of the classical conditioning process, the previously neutral stimulus is repeatedly paired with the unconditioned stimulus. As a result of this pairing, an association between the previously neutral stimulus and the UCS is formed.

At this point, the once neutral stimulus becomes known as the conditioned stimulus (CS). The subject has now been conditioned to respond to this stimulus. The conditioned stimulus is a previously neutral stimulus that, after becoming associated with the unconditioned stimulus, eventually comes to trigger a conditioned response.

In our earlier example, suppose that when you smelled your favorite food, you also heard the sound of a whistle. While the whistle is unrelated to the smell of the food, if the sound of the whistle was paired multiple times with the smell, the whistle sound would eventually trigger the conditioned response. In this case, the sound of the whistle is the conditioned stimulus.

The during conditioning phase involves repeatedly pairing a neutral stimulus with an unconditioned stimulus. Eventually, the neutral stimulus becomes the conditioned stimulus.

Phase 3: After Conditioning

Once the association has been made between the UCS and the CS, presenting the conditioned stimulus alone will come to evoke a response—even without the unconditioned stimulus. The resulting response is known as the conditioned response (CR).

The conditioned response is the learned response to the previously neutral stimulus. In our example, the conditioned response would be feeling hungry when you heard the sound of the whistle.

In the after conditioning phase, the conditioned stimulus alone triggers the conditioned response.

Behaviorists have described a number of different phenomena associated with classical conditioning. Some of these elements involve the initial establishment of the response while others describe the disappearance of a response. Here is a closer look at five key principles of classical conditioning.

Acquisition

Acquisition is the initial stage of learning, when a response is first established and gradually strengthened. During the acquisition phase of classical conditioning, a neutral stimulus is repeatedly paired with an unconditioned stimulus.

As you may recall, an unconditioned stimulus is something that naturally and automatically triggers a response without any learning. After an association is made, the subject will begin to emit a behavior in response to the previously neutral stimulus, which is now known as a conditioned stimulus. It is at this point that we can say that the response has been acquired.

Once the response has been established, you can gradually reinforce the response to make sure the behavior is well learned.

Extinction is when the occurrences of a conditioned response decrease or disappear. In classical conditioning, this happens when a conditioned stimulus is no longer paired with an unconditioned stimulus.

For example, if the smell of food (the unconditioned stimulus) had been paired with the sound of a whistle (the conditioned stimulus), the sound of the whistle would eventually come to evoke the conditioned response of hunger.

However, if the smell of food were no longer paired with the whistle, eventually the conditioned response (hunger) would disappear.

Spontaneous Recovery

Sometimes a learned response can suddenly reemerge, even after a period of extinction. This is called spontaneous recovery.

For example, imagine that after training a dog to salivate to the sound of a bell, you stop reinforcing the behavior and the response becomes extinct. After a rest period during which the conditioned stimulus is not presented, you ring the bell and the animal spontaneously recovers the previously learned response.

If the conditioned stimulus and unconditioned stimulus are no longer associated, extinction will return very rapidly after a spontaneous recovery.

Generalization

Stimulus generalization is the tendency for a conditioned stimulus to evoke similar responses after the response has been conditioned. For example, if a dog has been conditioned to salivate at the sound of a bell, the animal may also exhibit the same response to a sound that's similar to the bell.

In John B. Watson's famous  Little Albert Experiment , for example, a small child was conditioned to fear a white rat. The child demonstrated stimulus generalization by also exhibiting fear in response to other fuzzy white objects, including stuffed toys and Watson's own hair.

Discrimination

Discrimination is the ability to differentiate between a conditioned stimulus and other stimuli that have not been paired with an unconditioned stimulus.  

For example, if a bell tone were the conditioned stimulus, discrimination would involve being able to tell the difference between the bell tone and other similar sounds. Because the subject is able to distinguish between these stimuli, they will only respond when the conditioned stimulus is presented.

What Are Examples of Classical Conditioning?

It can be helpful to look at a few examples of how the classical conditioning process operates both in experimental and real-world settings.

Fear Response

John B. Watson's experiment with Little Albert is an example of the fear response. The child initially showed no fear of a white rat, but after the rat was paired repeatedly with loud, scary sounds, the child began to cry when the rat was present.

Prior to the conditioning, the white rat was a neutral stimulus. The unconditioned stimulus was the loud, clanging sounds, and the unconditioned response was the fear response created by the noise.

By repeatedly pairing the rat with the unconditioned stimulus, the white rat (now the conditioned stimulus) came to evoke the fear response (now the conditioned response).

This experiment illustrates how phobias can form through classical conditioning. In many cases, a single pairing of a neutral stimulus (a dog, for example) and a frightening experience (being bitten by the dog) can lead to a lasting phobia (being afraid of dogs).

Taste Aversions

Another example of classical conditioning is the development of conditioned taste aversions . Researchers John Garcia and Bob Koelling first noticed this phenomenon when they observed how rats that had been exposed to nausea-causing radiation developed an aversion to flavored water after the radiation and water were presented together.

In this example, the radiation represents the unconditioned stimulus and nausea represents the unconditioned response. After the pairing of the two, the flavored water is the conditioned stimulus, while nausea that formed when exposed to the water alone is the conditioned response.

Later research demonstrated that such classically conditioned aversions could be produced through a single pairing of the conditioned stimulus and the unconditioned stimulus.

Researchers also found that such aversions can even develop if the conditioned stimulus (the taste of the food) is presented several hours before the unconditioned stimulus (the nausea-causing stimulus).

Why do such associations develop so quickly? Forming such associations can have survival benefits. If an animal eats something that makes it ill, it needs to avoid eating the same food in the future to avoid sickness or even death.

This is an example of biological preparedness . Some associations form more readily because they aid in survival.

In one famous field study, researchers injected sheep carcasses with a poison that would make coyotes sick but not kill them. The goal was to help sheep ranchers reduce the number of sheep lost to coyote killings.

Not only did the experiment work by lowering the number of sheep killed, it also caused some of the coyotes to develop such a strong aversion to sheep that they would actually run away at the scent or sight of a sheep.

Organizational Behavior

Classical conditioning can also have applications in business and marketing. For example, it can be used to help people form favorable attitudes toward products, businesses, or brands.

While there may not be a direct link between the item and the consumer response, creating this association may help motivate people to purchase certain products because they have developed a favorable opinion of them due to classical conditioning.

Operant conditioning is a learning method in which a specific behavior is associated with either a positive or negative consequence. This form of learning links voluntary actions with receiving either a reward or punishment, often to strengthen or weaken those voluntary behaviors.

Classical conditioning is a learning process focused more on involuntary behaviors, using associations with neutral stimuli to evoke a specific involuntary response.

Criticisms of Classical Conditioning

Some psychologists maintain that classical conditioning represents a reductive, mechanical explanation for some behaviors. Some other criticisms of classical conditioning center on the fact that:

• Classical conditioning does not take human individuality and free will into account
• It generally does not predict human behavior; people can form associations but still not act upon them
• Many different factors can impact the associations and outcomes
• People can choose to not act on the associations they have made through classical conditioning

However, the approach still holds great fascination for researchers and relevance in modern psychology.

In reality, people do not respond exactly like Pavlov's dogs . There are, however, numerous real-world applications for classical conditioning. For example, many dog trainers use classical conditioning techniques to help people train their pets.

These techniques are also useful for helping people cope with phobias or anxiety problems . Therapists might, for example, repeatedly pair something that provokes anxiety with relaxation techniques in order to create an association.

Teachers can apply classical conditioning in the class by creating a positive classroom environment to help students overcome anxiety or fear. Pairing an anxiety-provoking situation, such as performing in front of a group, with pleasant surroundings helps the student learn new associations. Instead of feeling anxious and tense in these situations, the child will learn to stay relaxed and calm.

Ivan Pavlov discovered classical conditioning. Pavlov was passionate about physiology, even earning gold medals for his work in this field. It was in his position as director of a physiological laboratory that he began to connect physiological research with reflex response and regulation.

Implicit memory is a memory that you can recall effortlessly or without thought. Classical conditioning uses this automatic memory to create associations with a neutral stimulus. The association is learned without conscious awareness.

Behavioral therapies use the principles of classical conditioning to help people change negative behaviors. The thought behind these therapies is that we learn from our environment. Cognitive behavioral therapy and exposure therapy are two types of behavioral therapy.

Wolpe J, Plaud JJ. Pavlov's contributions to behavior therapy. The obvious and not so obvious. Am Psychol. 1997;52(9):966-72.

Windholz G. Pavlov on the conditioned reflex method and its limitations. Am J Psychol. 1995;108(4):575-88.

Holland JG. Behaviorism: Part of the problem or part of the solution . J Appl Behav Anal. 1978;11(1):163-74. doi:10.1901/jaba.1978.11-163

Rouleau N, Karbowski LM, Persinger MA. Experimental evidence of classical conditioning and microscopic engrams in an electroconductive material . PLoS ONE. 2016;11(10):e0165269. doi:10.1371/journal.pone.0165269

Morè L, Jensen G. Acquisition of conditioned responding in a multiple schedule depends on the reinforcement's temporal contingency with each stimulus . Learn Mem. 2014;21(5):258-62. doi: 10.1101/lm.034231.113

Lattal KM, Lattal KA. Facets of Pavlovian and operant extinction . Behav Processes. 2012;90(1):1-8. doi:10.1016/j.beproc.2012.03.009

Thanellou A, Green JT. Spontaneous recovery but not reinstatement of the extinguished conditioned eyeblink response in the rat . Behav Neurosci. 2011;125(4):613-25. doi:10.1037/a0023582

Dunsmoor JE, Mitroff SR, Labar KS. Generalization of conditioned fear along a dimension of increasing fear intensity . Learn Mem. 2009;16(7):460-9. doi:10.1101/lm.1431609

Murray JE, Li C, Palmatier MI, Bevins RA. The interoceptive Pavlovian stimulus effects of caffeine . Pharmacol Biochem Behav. 2007;86(4):838-46. doi:10.1016/j.pbb.2007.03.013

Hofmann SG. Cognitive processes during fear acquisition and extinction in animals and humans: implications for exposure therapy of anxiety disorders . Clin Psychol Rev. 2008;28(2):199-210. doi:10.1016/j.cpr.2007.04.009

Lin JY, Arthurs J, Reilly S. Conditioned taste aversion, drugs of abuse and palatability . Neurosci Biobehav Rev . 2014;45:28-45. doi:10.1016/j.neubiorev.2014.05.001

Åhs F, Rosén J, Kastrati G, Fredrikson M, Agren T, Lundström JN. Biological preparedness and resistance to extinction of skin conductance responses conditioned to fear relevant animal pictures: A systematic review . Neurosci Biobehav Rev. 2018;95:430-437. doi:10.1016/j.neubiorev.2018.10.017

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By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

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• Behavioral Psychology

Pavlov's Dogs and Classical Conditioning

How pavlov's experiments with dogs demonstrated that our behavior can be changed using conditioning..

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One of the most revealing studies in behavioral psychology was carried out by Russian physiologist Ivan Pavlov (1849-1936) in a series of experiments today referred to as 'Pavlov's Dogs'. His research would become renowned for demonstrating the way in classical conditioning (also referred to as Pavlovian conditioning ) could be used to cultivate a particular association between the occurrence of one event in the anticipation of another.

• Conditioning
• Stimulus-Response Theory
• Reductionism in Psychology
• What Factors Affect Classical Conditioning?
• Imprinting and Relationships

Pavlov's Dog Experiments

Pavlov came across classical conditioning unintentionally during his research into animals' gastric systems. Whilst measuring the salivation rates of dogs, he found that they would produce saliva when they heard or smelt food in anticipation of feeding. This is a normal reflex response which we would expect to happen as saliva plays a role in the digestion of food.

Did You Know?

Psychologist Edwin Twitmyer at the University of Pennsylvania in the U.S. discovered classical conditioning at approximately the same time as Pavlov was conducting his research ( Coon, 1982 ). 1 However, the two were unaware of each other's research in this case of simultaneous discovery , and Pavlov received credit for the findings.

However, the dogs also began to salivate when events occurred which would otherwise be unrelated to feeding. By playing sounds to the dogs prior to feeding them, Pavlov showed that they could be conditioned to unconsciously associate neutral, unrelated events with being fed 2 .

Experiment Procedure

Pavlov's dogs were each placed in an isolated environment and restrained in a harness, with a food bowl in front of them and a device was used to measure the rate at which their saliva glands made secretions. These measurements would then be recorded onto a revolving drum so that Pavlov could monitor salivation rates throughout the experiments.

He found that the dogs would begin to salivate when a door was opened for the researcher to feed them.

This response demonstrated the basic principle of classical conditioning . A neutral event, such as opening a door (a neutral stimulus , NS) could be associated with another event that followed - in this case, being fed (known as the unconditioned stimulus , UCS). This association could be created through repeating the neutral stimulus along with the unconditioned stimulus, which would become a conditioned stimulus , leading to a conditioned response : salivation.

Pavlov continued his research and tested a variety of other neutral stimuli which would otherwise be unlinked to the receipt of food. These included precise tones produced by a buzzer, the ticking of a metronome and electric shocks .

The dogs would demonstrate a similar association between these events and the food that followed.

NEUTRAL STIMULUS (NS, eg. tone) > UNCONDITIONED STIMULUS (UCS, eg. receiving food)

when repeated leads to:

CONDITIONED STIMULUS (CS, eg. tone) > CONDITIONED RESPONSE (CR, eg. salivation)

The implications for Pavlov's findings are significant as they can be applied to many animals, including humans.

For example, when you first saw someone holding a balloon and a pin close to it, you may have watched in anticipation as they burst the balloon. After this had happened multiple times, you would associate holding the pin to the balloon with the 'bang' that followed. Like Pavlov's dogs, classical conditioning was leading you to associate a neutral stimulus (the pin approaching a balloon) with bursting of the balloon, leading to a conditioned response (flinching, wincing or plugging one's ears) to this now conditioned stimulus.

• Craik & Lockhart (1972) Levels of Processing Theory

Let us look now at some of the nuances of Pavlov's findings in relation to classical conditioning.

'Unconditioning' through experimental extinction

Once an animal has been inadvertently conditioned to produce a response to a stimulus, can this association ever be broken?

Pavlov presented the dogs with a tone which they would come to associate with food. He then played the tone but did not follow that by rewarding the dogs with food.

After he made the sound without food numerous times, the dogs' produced less saliva as the conditioning underwent experimental extinction - a case of 'unlearning' the association.

When experimental extinction occurs, is the association permanently broken?

Pavlov's research would suggest that it remains but is inactive after extinction, and can be re-activated by reinstating, for example, the food reward, as it was given during the original conditioning. This phenomenon is known as spontaneous recovery .

Forward Conditioning vs Backward Conditioning

During conditioning, it is important that the neutral stimulus (NS) is presented before the unconditioned stimulus (UCS) in order for learning to take place. This forward conditioning is more likely to lead to a conditioned response than when the neutral stimulus is presented after the conditioned stimulus has been provided ( backward conditioning ).

In the case of Pavlov's dogs, the tone must be played to the subject prior to the food being provided. Making a sound after the dogs have been fed may not lead to a conditioned association being made between the events.

Carr and Freeman (1919) attempted both forward and backward conditioning in rats, between a buzzer sound and closed doors in a maze. They found backward conditioning to be ineffective when compared to forward conditioning. 4

Delay Conditioning vs Trace Conditioning

We may use forward conditioning in one of two forms:

Delay Conditioning - when the unconditioned stimulus is provided prior to and during the unconditioned stimulus - there is a period of overlap where the neutral and unconditioned stimulus are given simultaneously, e.g. a buzzer sound begins, and after 10 seconds, food is given whilst the buzzer continues.

Trace Conditioning - when there is a delay after the unconditioned stimulus has been provided before the unconditioned stimulus is presented to the subject, e.g. buzzer sounds for 10 seconds, stops and after 10 seconds of silence (the trace interval ), food is presented.

Discussing delay conditioning, Pavlov (1927) asserted that the longer the delay between the stimuli, the more delayed the response would be 5 .

Temporal Conditioning

So far, we have looked at conditioning in which a neutral stimulus is key to eliciting a desired response. However, if an unconditioned stimulus is provided at regular intervals, even without a preceding neutral stimulus, animals' sense of timing will enable conditioning to take place, and a response may occur in time with the intervals.

For example, in a study in which rats were fed at either random or regular intervals, Kirkpatrick and Church (2003) found that the subjects underwent temporal conditioning in the anticipation of food when they were fed at set intervals. 6

Generalisation

Pavlov noticed that once neutral stimulus had been associated with an unconditioned stimulus, the conditioned stimulus could vary and the dogs would still generate a similar response. For example, once specific tone of buzzer sound was associated with food, differing toned buzzer sounds would solicit a conditioned response.

Nonetheless, the closer the stimulus was to the original stimulus used in conditioning, the clearer the response would be. This correlation between stimulus accuracy and response is referred to as a generalisation gradient , and has been demonstrated in studies such as Meulders et al (2013) . 7

Modern Classical Conditioning

Pavlov's dog experiments are still discussed today and have influenced many later ideas in psychology. The U.S. psychologist John B. Watson was impressed by Pavlov's findings and reproduced classical conditioning in the Little Albert Experiment (Watson, 1920), in which a subject was unethically conditioned to associate furry stimuli such as rabbits with a loud noise, and subsequently developed a fear of rats. 8

• Behavioral Approach

The numerous studies following the experiments, which have demonstrated classical conditioning using a variety of methods, also show the replicability of Pavlov's research, helping it to be recognised as an important unconscious influence of human behavior. This has helped the theory to be recognised and applied in many real life situations, from training dogs to creating associations in today's product advertisements.

Continue Reading

• Coon, D.J. (1982). Eponymy, obscurity, Twitmyer, and Pavlov. Journal of the History of Behavioral Science . 18 (3). 255-62.
• Pavlov, I.P. (1927). Conditioned Reflexes: An investigation of the physiological activity of the cerebral cortex. Retrieved from http://psychclassics.yorku.ca/Pavlov/ .
• Craik, F.I.M. and Lockhart, R.S. (1972). Levels of Processing: A Framework for Memory Research. Journal of Verbal Learning and Visual Behavior . 11 (6). 671-684.
• Carr, H. and Freeman A. (1919). Time relationships in the formation of associations. Psychology Review . 26 (6). 335-353.
• Pavlov, I.P. (1927). Conditioned Reflexes: An investigation of the physiological activity of the cerebral cortex. Retrieved from http://psychclassics.yorku.ca/Pavlov/lecture6.htm .
• Kirkpatrick, K and Church, R.M. (2003). Tracking of the expected time to reinforcement in temporal conditioning processes. Learning & Behavior . 31 (1). 3-21.
• Meulders A, Vandebroek, N. Vervliet, B. and Vlaeyen, J.W.S. (2013). Generalization Gradients in Cued and Contextual Pain-Related Fear: An Experimental Study in Health Participants. Frontiers in Human Neuroscience , 7 (345). 1-12.
• Watson, J.B. and Rayner, R. (1920). Conditioned Emotional Reactions. Journal of Experimental Psychology . 3 (1). 1-14.
• Watson, J.B. (1913). Psychology as the Behaviorist Views It. Psychological Review . (Watson, 1913). 20 . 158-177.

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• Fight-or-Flight Response
• Neuroticism Test

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