The Stimulus-Organism-Response Theory

The Stimulus-Organism-Response theory is a psychological model that describes how individuals respond to stimuli in their environment. This theory was initially introduced by Robert S. Woodworth in 1918. It was further developed and applied in consumer behavior in 1974 by Albert Mehrabian and James A. Russel.

The Stimulus-Organism-Response theory or SOR Theory demonstrates that stimuli from the environment (S) affect the organism (O), which then leads to a response (R) (Mehrabian & Russell, 1974) (Figure 1).

  • Stimulus (S): External factors/environmental events trigger a response (Mehrabian & Russell, 1974). Stimuli can be things in the environment, such as smell, taste, or touch. In advertising, stimuli can be visual advertisements, auditory messages, or other forms of communication that individuals encounter.
  • Organism (O): The internal state of an individual, including psychological and physiological factors, which brings about the relationship between stimuli and responses (Mehrabian & Russell, 1974). In advertising, organisms/internal factors include emotions, attitudes, beliefs, perceptions, and cognitive processes that affect how an individual responds to external stimuli (Woodworth, 1918).
  • Response (R): The behavior or reaction that occurs because of the interaction between stimuli and the organism (Mehrabian & Russell, 1974). These responses can be cognitive (e.g., thoughts), affective (e.g., emotional reactions), or behavioral actions.

Figure 1: SOR Model (Mehrabian & Russel, 1974)

The Stimulus-Organism-Response theory comprises different postulates. First, different stimuli may evoke varying responses based on their visual, auditory, or other sensory inputs (Tan, 2019). This could be very useful for advertisers as they can research different stimuli to make their target audience feel what they want. On the contrary, it can be detrimental for advertisers to a campaign if they do not examine how certain stimuli could affect their target audience. Second, the same stimulus could lead to different responses depending on the individual's internal state (Tan, 2019). However, the internal state of the target audience is influenced by multiple factors that are out of the advertiser's control. Third, some factors influence the relationship between stimuli and responses. These mediating variables, such as motivation or attention, can impact the strength or direction of the S-O-R relationships (Tan, 2019). S-O-R can be integrated with other theories to enhance its explanatory power, such as combining it with social cognitive theories like the heuristic-systematic model (Chen & Chaiken, 1999), that could explain the mediating processes. Fourth, there are temporal dynamics in that the responses may change over time, and the timing of stimuli can affect the strength of the connection between stimulus and response (Tan, 2019).

Understanding the S-O-R theory can guide practical applications in advertising and marketing by tailoring stimuli to elicit desired responses. The S-O-R theory is particularly useful in advertising because it helps marketers understand how different stimuli, such as advertisements, affect individuals' internal states and, subsequently, their behaviors. Then, the S-O-R theory is a valuable tool for understanding and predicting responses to stimuli. Still, its effectiveness depends on careful consideration of its aspects and conditions, as well as integration with complementary theories. For instance, Hashmi et al. (2019) showed that the impact of website quality dimensions (the stimulus) on online impulsive buying behavior (the response) is mediated by shopping values (the organism). In other words, their research demonstrated that hedonic and utilitarian values mediate the relationship between website quality dimensions and online impulsive buying behavior.

In summary, the Stimulus-Organism-Response theory is a comprehensive framework that helps explain human behavior by considering the interplay between external stimuli, internal states, and observable responses. It provides insights into the complexity of human reactions and has practical applications in understanding and influencing consumer behavior.


Chen, S., & Chaiken, S. (1999). The heuristic-systematic model in its broader context. In S. Chaiken & Y. Trope (Eds.), Dual-process theories in social psychology (pp. 73–96). The Guilford Press.

Hashmi, H., Attiq, S., & Rasheed, F. (2019). Factors affecting online impulsive buying behavior: A stimulus organism response model approach. Market Forces, 14(1).

Mehrabian, A., & Russell, J. A. (1974). An approach to environmental psychology. The MIT Press.

Tan, C. C. (2019). Intercepting stimulus-organism-response model, theory of planned behavior and theory of expectancy confirmation in the study of smartphone consumer behavior: A Thai university student perspective. Asia Pacific Journal of Religions and Cultures, 3(2), 27-48.

Woodworth, R. S. (1918). Dynamic psychology. New York, NY: Columbia University Press.