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Stimulus Generalization in Psychology

What is Stimulus Generalization

Stimulus generalization occurs when an organism’s response previously conditioned by one stimulus can then be evoked by another stimulus having similar characteristics​1​.

When organisms encounter stimuli similar to those they’ve encountered previously, they respond in the same way. Their responses have generalized to other stimuli.

In a classical conditioning process, a neutral stimulus is paired with an unconditioned stimulus. Then during the generalization phase, it becomes a conditioned stimulus that can trigger a conditioned response without going through the learning process. 

In similarity-based stimulus generalization, untrained stimuli that are similar to the conditioned stimulus become conditioned without being directly conditioned.

For example, After being bitten by a poodle, a person becomes afraid of poodles and other types of dogs. The same fear can be triggered by a pug, even though it is a different breed, has a different color, and looks different.

white rat

Stimulus generalization examples

Little Albert Experiment

Here is a famous psychology experiment.

A small child, named Albert, was afraid of loud noises, but not of white rats. In the Little Albert Experiment, Watson and Raynor paired the white rat with a loud noise to condition him to fear it.

Albert eventually developed a fear response, but it was not only white rats he feared but white rabbits and a seal fur coat as well.

The fear he has for white rats has generalized to other items of a similar nature​2​.

Phobia and Posttraumatic Stress Disorder (PTSD)

Fear is an adaptive emotion that serves as a safeguard against potential dangers. Through classical conditioning, humans learn to instinctively avoid dangerous stimulus in the environment that signals danger.

It is, therefore, normal that traumatic events can cause the brain to become conditioned to fear cues present at the event. However, this natural instinct toward threatening stimuli turns into irrational fear when the fear generalizes to harmless stimuli​3​.

The resulting phobia or PTSD becomes a burden to daily life. The sufferers are unable to cope with the fear generalization, a result of a wider generalization.

If a cup was present when the trauma occurred, visual stimuli like a cup or a glass can trigger flashbacks and intrusive thoughts in the victim.

Private-label products

Private label products are products that grocery stores create to compete with nationally branded items. Most of these products copy the packaging of leading brands, including the colors, shapes, and fonts.

Consumers’ positive attitudes and trust in the leading products can be transferred to private-label products through stimulus generalization. Copycat products capitalize on the brand’s recognition​4​.

Food aversion

Food aversion is an adaptive behavior that prevents us from ingesting bad food. Scientists have found that almost all species, including humans, generalize food aversion​5​.

For instance, a person feels sick after eating a bad peach. This makes him afraid of eating another peach. But he also becomes conditioned to fear eating nectarines because they look very much like peaches.

Pavlov’s dogs

Pavlov’s Dogs Experiment is another classic experiment in showing conditioning and stimulus generalization.

Pavlov was studying saliva and gastric secretions in dogs when he digressed to another experiment. He rang a bell before presenting food. 

The dog learned to associate the sound with food and salivated on hearing the bell even without seeing the food. Classical stimulus generalization happened when it also responded in the same way to other high-pitched sounds​6​.

Behavior modification and generalization in children

The stimulus generalization mechanism can be applied to both classical conditioning and operant conditioning. Parents often use this special property to discipline their children.

Behaviorists believe that a child’s pattern of behavior should change based on its consequence.

Parents teach their children to say ‘please’ when asking for something and ‘thank you’ when being given it using reinforcement. Therefore, learning in one setting can be generalized to other settings, such as schools, playgrounds, and libraries.

However, behavior modification such as this doesn’t always work​7​.

Behaviorism rarely works or lasts because it is based on the assumption that behavior can be changed using reinforcement such as rewards or punishment.

But in reality, children, and humans, are more complex than that.

When a parent is kind and respectful to their child at home, the child easily follows the teaching, saying please and thank you when reinforcement is used. 

However, if a teacher is mean and strict, the child may show different behavior at school despite receiving the same reinforcement. Individual differences in experiences, likings, and circumstances can all affect the child’s decision and classroom behavior.

Stimulus generalization vs response generalization

The key difference between stimulus generalization and response generalization is that stimulus generalization occurs when multiple stimuli can generate the same response, while response generalization occurs when the same stimulus can generate multiple similar responses.

Both of them are important associative learning mechanisms.

For example, reading words is often taught in isolation, but students can generalize this skill to read full sentences and this is stimulus generation. Response generalization occurs when students spell words that are not explicitly instructed after they have learned to read these words​8,9​.

Children learning to tie their shoes show another stimulus generalization pattern. Having learned how to tie one pair of shoes, children can do the same with other types of shoes.

Response generalization occurs when children apply their newly acquired tying skills to tie a bow on a gift.

Stimulus generalization vs stimulus discrimination

The main difference between stimulus generalization and discrimination is that stimulus generalization refers to multiple stimuli generating the same response while stimulus discrimination refers to different stimuli generating distinct responses.

In school, a student stops running when any teacher tells them to. No matter who the teacher is, he responds the same way. This is stimulus generalization. When the child is at home, however, he only stops running when his mother tells him to but ignores when his father tells him to. This is stimulus discrimination.


  1. 1.
    Mednick SA, Freedman JL. Stimulus generalization. Psychological Bulletin. Published online May 1960:169-200. doi:10.1037/h0041650
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    Watson JB, Rayner R. Conditioned emotional reactions. Journal of Experimental Psychology. Published online February 1920:1-14. doi:10.1037/h0069608
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    Dunsmoor JE, Paz R. Fear Generalization and Anxiety: Behavioral and Neural Mechanisms. Biological Psychiatry. Published online September 2015:336-343. doi:10.1016/j.biopsych.2015.04.010
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    Till BD, Priluck RL. Stimulus generalization in classical conditioning: An initial investigation and extension. Psychology & Marketing. 2000;17(1):55–72.
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    LOGUE AW. Conditioned Food Aversion Learning in Humans. Ann NY Acad Sci. Published online June 1985:316-329. doi:10.1111/j.1749-6632.1985.tb27082.x
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    Jinks J, Lorsbach A. INTRODUCTION: MOTIVATION AND SELF-EFFICACY BELIEF. Reading & Writing Quarterly. Published online April 2003:113-118. doi:10.1080/10573560308218
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    Duhon GJ, House SE, Poncy BC, Hastings KW, McClurg SC. An Examination of Two Techniques for Promoting Response Generalization of Early Literacy Skills. J Behav Educ. Published online January 28, 2010:62-75. doi:10.1007/s10864-010-9097-2
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    Arnold-Saritepe AM, Phillips KJ, Mudford OC, De Rozario KA, Taylor SA. Generalization and Maintenance. Applied Behavior Analysis for Children with Autism Spectrum Disorders. Published online 2009:207-224. doi:10.1007/978-1-4419-0088-3_12


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