The field of I-O psychology had its birth in industrial psychology and the use of psychological concepts to aid in personnel selection. However, with research such as the Hawthorne study, it was found that productivity was affected more by human interaction and not physical factors; the field of industrial psychology expanded to include organizational psychology. Both WWI and WWII had a strong influence on the development of an expansion of industrial psychology in the United States and elsewhere: The tasks the psychologists were assigned led to development of tests and research in how the psychological concepts could assist industry and other areas. This movement aided in expanding industrial psychology to include organizational psychology.
Industrial psychology studies the attributes of jobs, applicants of those jobs, and methods for assessing fit to a job. These procedures include job analysis, applicant testing, and interviews. It also studies and puts into place procedures for the orientation of new employees and ongoing training of employees. The process of hiring employees can be vulnerable to bias, which is illegal, and industrial psychologists must develop methods for adhering to the law in hiring. Performance appraisal systems are an active area of research and practice in industrial psychology.
Organizational psychology is concerned with the effects of interactions among people in the workplace on the employees themselves and on organizational productivity. Job satisfaction and its determinants and outcomes are a major focus of organizational psychology research and practice. Organizational psychologists have also studied the effects of management styles and leadership styles on productivity. In addition to the employees and management, organizational psychology also looks at the organizational culture and how that might affect productivity. One aspect of organization culture is the prevention and addressing of sexual and other forms of harassment in the workplace. Sexual harassment includes language, behavior, or displays that create a hostile environment; it also includes sexual favors requested in exchange for workplace rewards (i.e., quid pro quo). Industrial-organizational psychology has conducted extensive research on the triggers and causes of workplace violence and safety. This enables the organization to establish procedures that can identify these triggers before they become a problem.
Human factors psychology, or ergonomics, studies the interface between workers and their machines and physical environments. Human factors psychologists specifically seek to design machines to better support the workers using them. Psychologists may be involved in design of work tools such as software, displays, or machines from the beginning of the design process or during the testing an already developed product. Human factor psychologists are also involved in the development of best design recommendations and regulations. One important aspect of human factors psychology is enhancing worker safety. Human factors research involves efforts to understand and improve interactions between technology systems and their human operators. Human–software interactions are a large sector of this research.