This model was originated in the late 1950's by three United States social psychologists. The Health Belief Model (HBM) tries to identify how individuals think and if they will take certain healthful actions given adequate information. Perceived susceptibility, perceived severity, perceived benefits, and perceived barriers are the four terms that help construct the HBM. This model emphasizes the “role of perceptions of vulnerability to an illness and the potential effectiveness in treatment”. An individual’s health behavior is related to whether they perceive themselves to be susceptible to a health problem, see this problem as serious, are convinced they will benefit from treatment or prevention activities and recognize the need to take action and any barriers that would interfere with this action. As all models, the HBM has both strengths and weaknesses. Evidence of its success has been seen in primary prevention sexuality education programs and in surveys done to examine why or why not individuals engage in certain health-related behaviors. Its main limitation is its ability to predict future behaviors. Its main applications include exploration of sexual risk behaviors and the transmission of HIV/AIDS.