Pavlov’s Dog Experiment: For Whom the Bell Tolls


Riona is spending the day at a local carnival with her friends. The first thing she decides to do is buy her favorite fair food: funnel cake, loaded with plenty of powdered sugar and cinnamon. After eating the funnel cake, Riona waits for half an hour to digest the food before going on a super-popular new roller coaster called The Thrasher that violently twists and turns and loops around. Immediately after getting off the ride, Riona experiences nausea and an upset stomach. 

Looking at the situation from a logical perspective, most people would agree that Riona’s nausea was most likely caused by the intense motion of the roller coaster, not food poisoning from the funnel cake. But if that’s true, why does the smallest taste of funnel cake now consistently make Riona nauseous after that day at the carnival? 

Here’s Why

The human brain has evolved to very quickly pick up on potential patterns in a person’s surroundings. What does this have to do with Riona’s predicament, you ask? Well, after her disastrous day at the carnival, Riona’s brain believed it had found a meaningful association between eating funnel cake and the intense motion of the roller coaster. The brain thought that perhaps these two actions always happen in this exact sequence and assumed that whenever Riona eats funnel cake, this is a sure sign that she will get on a rollercoaster soon after and become nauseous. The brain now identifies the taste of funnel cake as a good predictor of future nausea and creates a mental shortcut so that eating funnel cake will now immediately lead to nausea for Riona. This is a simplified explanation of how the psychological process of classical conditioning happens. 


Classical conditioning, a learning process discovered by Russian physiologist Ivan Pavlov, occurs when an environmental stimulus which is not biologically-wired to get a certain response is repeatedly paired with a natural stimulus that is biologically-wired to get a response. After several repetitions of first presenting the environmental stimulus and then the natural stimulus to an animal, that organism will now give a response even when only presented with the environmental stimulus. 

The History

Since Ivan Pavlov was originally a physiologist, not a psychologist, he was in the middle of studying how the digestion process works in dogs when he realized that the dogs he was working with would already start drooling at the footstep-sounds of the assistant who fed them—not just when food was actually placed in front of them. Intrigued by this new observation, Pavlov decided to structure a whole new experiment around making the dogs salivate in response to other random sounds. 

Through his experimentation, Pavlov discovered a three-stage process to classical conditioning. In Stage 1: Before Conditioning, Pavlov presents the dog with food, which is an unconditioned stimulus, or an item that will elicit an uncontrollable, innate reaction. The uncontrollable, innate reaction itself is known as the unconditioned response, which in this case is salivation. After the dog has calmed back down to its original state, Pavlov presents it with a ticking metronome, and the dog does nothing. Thus, the metronome is currently a neutral stimulus, or an item that elicits no reaction. 

In Stage 2: Conditioning, Pavlov first presents the dog with the metronome, then with the food (which the dog is allowed to eat), and repeats this sequence multiple times. Using more technical terms, Pavlov pairs the previously neutral stimulus with the unconditioned stimulus and does multiple experimental trials of this procedure. Now, the dog’s brain identifies the metronome’s ticking as an accurate predictor for when food will be served. 

In Stage 3: After Conditioning, Pavlov presents the dog with just the metronome, and it starts salivating even though there’s no food in sight. This means that the metronome’s ticking, which was previously a neutral stimulus, has now become a conditioned stimulus, or an item that an animal has been trained to respond to. When the dog salivates after hearing the ticking, this is a conditioned response because it’s a learned reaction, not a naturally instinctive one. 

Applying It

The principles learned from Pavlov’s experiment are significant because of their wide applicability. For example, they were used to create behavioral therapy programs for psychiatric patients. People who experience severe anxiety or fear in response to certain stimuli, like racial slurs or spiders, might undergo a process called counterconditioning, in which patients are exposed to triggering stimuli in controlled amounts and trained to respond to them in a calm manner. Essentially, psychiatrists try to eliminate phobias and decrease the intensity of anxiety attacks by interrupting the patient’s current stimulus-response pattern in which they respond to triggers like slurs and spiders with accelerated heart rate, lightheadedness, etc. and replacing it with a new stimulus-response pattern in which they remain calm in response to those triggers. 

Pavlov’s research on classical conditioning has also been extremely vital to understanding how drug and alcohol overdoses and addictions can happen. In this case, the alcohol or drug is the unconditioned stimulus, and the body’s production of enzymes to break down the alcohol or drug is the unconditioned response. Since alcohol and drugs (whether prescription-based or illegal) are typically only consumed at specific times and places, various elements of an addict’s surroundings can easily become conditioned stimuli over time without them even realizing. 

For example, let’s look at a person who only drinks alcohol at college parties. Stimuli that are specific to this environment, such as dim lighting, loud music, and the visual image of red plastic cups, always bombard the person right before he drinks, and thus become conditioned stimuli. Now, whenever this guy’s in a dark room, listens to loud music, or sees a red cup, his liver starts producing that special enzyme used to break down alcohol before he even drinks. This means that he will process alcohol more quickly than before and have increasingly higher alcohol tolerance. He’ll need to drink a lot before he gets that “buzz,” and his chance of accidental overdose becomes much greater. The same thing would happen to a person consistently taking drugs in the same environment. Fighting addiction and overdose is not just about finding the willpower to overcome your problems—much of the complexity of addiction comes from the fact that your body and mind are programmed to easily fall into its trap, and it really can happen without you realizing.

Think Further

  1. Let’s say that you want to train your dog to salivate whenever you clap your hands. Explain the steps of how you might do this – be sure to mention what the unconditioned stimulus, unconditioned response, conditioned stimulus, and conditioned response are!
  2. Now you want to train your dog to cower whenever you clap your hands. Explain the steps of how you might do this – be sure to mention what the unconditioned stimulus, unconditioned response, conditioned stimulus, and conditioned response are!
  3. What is one possible real-life application of classical conditioning? 


Get updated about new videos!



Learn More

  1. Bichler, O., et al. “Pavlov’s Dog Associative Learning Demonstrated on Synaptic-Like Organic Transistors.” Neural Computation, vol. 25, no. 2, Sept. 2012, pp. 549–66. MIT Press Journals, doi:10.1162/NECO_a_00377.
  2. Krugman, Herbert E. “Pavlov’s Dog and the Future of Consumer Psychology.” Journal of Advertising Research, 1 Nov. 1994,
  3. Rehman, Ibraheem, et al. “Classical Conditioning.” StatPearls, StatPearls Publishing, 2019. PubMed,
  4. Schultz, Wolfram. “Behavioral Theories and the Neurophysiology of Reward.” Annual Review of Psychology, vol. 57, no. 1, 2006, pp. 87–115. Annual Reviews, doi:10.1146/annurev.psych.56.091103.070229.