Objective: Pathogen disgust has evolved as a psychological adaptation in response to the avoidance of disease-causing organisms. Recently, evolutionary social psychologists have proposed the existence of a behavioral immune system that has evolved to avoid pathogens as a psychological adaptation. However, researchers claim that the concept of a behavioral immune system is not the same as pathogen avoidance. Therefore, in this study, the aim is to investigate whether the behavioral immune system is the same as the pathogen avoidance system or has a broader meaning. Method: using Google Scholar database keywords such as disease avoidance, pathogen disgust, the behavioral immune system were searched. PubMed for the behavioral immune system, system over perception disease cues, and disease over perception bias was investigated. All-time periods were used for this review study and more than two hundred documents were reviewed and extracted according to the criteria. Results: The findings show that there are three main mechanisms involved in the behavioral immune system. This system includes the emotional, cognitive, and behavioral mechanisms. Therefore the results showed that the behavioral immune system has a broader meaning than the pathogen avoidance system. Conclusion: Research on physiological correlations with emotional experiences shows that disgust is evoked in response to pathogen-related stimuli and is associated with unique patterns of autonomic nervous system and neural activity. However little is known about the functional connections between anatomical structures, neurochemical processes, and various cognitive and behavioral phenomena that are the manifestations of the behavioral immune system, and more studies are needed in this area.
