Discrimination is the unfair or prejudicial treatment of people and groups based on characteristics such as race, gender, age, or sexual orientation. Discrimination is usually the behavioral manifestation of prejudice and involves negative, hostile, and injurious treatment of members of rejected groups.Stimulus discrimination is distinguishing between a learned stimulus and similar stimuli. Discrimination refers to an individual's unjustifiable action or behavior towards a group and its members, type of person, or thing. "Validation of the Detroit area study discrimination scale in a community sample of older African American adults: the Pittsburgh healthy heart project. Racial discrimination occurs when an employee or position applicant is treated wrongly because of their race, color, or nationality. Your mental illness may be serious if you have significant trouble completing projects and interacting with people at work, school, home and social settings. Discrimination, in psychology, the ability to perceive and respond to differences among stimuli. Definition of Organizational Psychology. After reading the assigned scenario, participants were asked to fill out post-scenario measures of emotions (e.g.