Stimulus generalization occurs when an organism responds to a stimulus in the same way that it responds to a similar stimulus. This occurs during the classical conditioning process.
For example, imagine a dog being conditioned to run to its owner when it hears a whistle. The dog responds similarly when it hears a small child emit a high-pitched shriek. This is an example of stimulus generalization. The animal responds to a similar stimulus in the same way it would to the conditioned stimulus.
Examples of Stimulus Generalization
To understand how stimulus generalization works in psychology, it can be helpful to look at a few different examples.
The Little Albert Experiment
One of the most famous examples of stimulus generalization occurred in an early psychology experiment. In the Little Albert experiment, the behaviorist John B. Watson and his assistant Rosalie Rayner conditioned a little boy to fear a white rat.
However, the boy would respond similarly when he saw similar items, such as a furry white toy and Watson’s white beard.
Ivan Pavlov’s famous experiment with dogs also demonstrated the effects of stimulus generalization. While studying dogs’ digestive systems, Pavlov realized that pairing the sound of a bell with the presentation of food would condition the dogs to salivate whenever they heard the bell.
When other similar-sounding noises were presented, the dogs would also salivate in response. In this example of stimulus generalization, the dogs generalized the conditioned stimulus (the sound of the bell) onto other similar high-pitched sounds.
Specific phobias can also be affected by stimulus generalization. For example, imagine that a dog bites a person and develops a phobia of dogs. They then experience fear responses whenever they see any small, furry, four-legged animal.
In this case, stimulus generalization has caused animals similar to a dog to trigger the same fear response.
Conditioned Food Aversions
Conditioned food aversions happen when someone develops an association between a food and getting sick (even if the food was not the source of the illness). After a single pairing of eating a food and becoming ill, people may avoid that food in the future.
Stimulus generalization might cause a person to avoid foods similar to the items they ate before getting sick. For example, if they became ill after eating a burrito, they might avoid eating burritos in the future, along with other foods wrapped in tortillas.
The Impact of Stimulus Generalization
Stimulus generalization can have an impact on how people respond to different stimuli. For example, imagine in school that children are expected to line up for lunch when they hear the ding of a bell.
However, another similar-sounding bell also rings when the kids are expected to sit at their desks for reading time.
If stimulus generalization occurs, the children will have trouble determining which response they are supposed to give. For example, the kids might all line up for lunch instead of sitting in their desks when the reading time bell sounds.
Because of this, stimulus discrimination is also important. This involves the ability to distinguish between two similar stimuli.
The school kids in our example might experience stimulus generalization at first, but as they become more familiar with their school schedule and the unique sound of each bell, they will eventually learn to discriminate between the two bells.
Researchers have found that stimulus generalization can also affect whether or not we trust others. If we learn to trust someone, we might trust people who resemble trustworthy individuals.
Stimulus Generalization vs. Stimulus Discrimination
Stimulus generalization and stimulus discrimination describe ways organisms respond to similar stimuli but differ in important ways. Generalization involves a broadening of the response so that the organisms respond to similar stimuli. Discrimination involves narrowing the response so that an organism can differentiate between two similar stimuli.
Key Points to Remember
Stimulus generalization can impact the learning process in both classical and operant conditioning. Sometimes this generalization can be a good thing. In school, kids may learn skills in one setting that can be transferred into similar situations.
In other cases, it can lead to confusion and complication if there is a need to distinguish between similar stimuli.
Fortunately, people can learn how to tell the differences between similar stimuli and avoid stimulus generalization if necessary.
Cuvo, A.J. On Stimulus Generalization and Stimulus Classes. Journal of Behavioral Education, 12, 77–83 (2003). https://doi.org/10.1023/A:1022374406394
FeldmanHall, O., Dunsmoor, J. E., Tompary, A., Hunter, L. E., Todorov, A., & Phelps, E. A. (2018). Stimulus generalization as a mechanism for learning to trust. Proceedings of the National Academy of Sciences, 115(7). https://doi.org/10.1073/pnas.1715227115
Eilifsen, C., & Arntzen, E. (2021). Mediated generalization and stimulus equivalence. Perspectives on Behavior Science, 44(1), 1–27. https://doi.org/10.1007/s40614-021-00281-3
Sigurðardóttir, Z. G., Mackay, H. A., & Green, G. (2012). Stimulus equivalence, generalization, and contextual stimulus control in verbal classes. The Analysis of Verbal Behavior, 28(1), 3–29. https://doi.org/10.1007/BF03393105
Kendra Cherry, MS.Ed., is an author, educator, and founder of Explore Psychology, an online psychology resource. She is a health writer and editor specializing in psychology, mental health, and wellness. She also writes for Verywell Mind and is the author of the Everything Psychology book (Adams Media).
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