Two-factor theory  The two-factor theory (also known as Herzberg's motivation-hygiene theory and dual-factor theory) states that there are certain factors in the workplace that cause job satisfaction while a separate set of factors cause dissatisfaction, all of which act independently of each other. It was developed by psychologist Frederick Herzberg. Feelings, attitudes and their connection with industrial mental health are related to Abraham Maslow's theory of motivation. His findings have had a considerable theoretical, as well as a practical, influence on attitudes toward administration. According to Herzberg, individuals are not content with the satisfaction of lower-order needs at work; for example, those needs associated with minimum salary levels or safe and pleasant working conditions. Rather, individuals look for the gratification of higher-level psychological needs having to do with achievement, recognition, responsibility, advancement, and the nature of the work itself. This appears to parallel Maslow's theory of a need hierarchy. However, Herzberg added a new dimension to this theory by proposing a two-factor model of motivation, based on the notion that the presence of one set of job characteristics or incentives leads to worker "satisfaction" at work, while another and separate set of job characteristics leads to "dissatisfaction" at work. Thus, satisfaction and dissatisfaction are not on a continuum with one increasing as the other diminishes, but are independent phenomena. This theory suggests that to improve job attitudes and productivity, administrators must recognize and attend to both sets of characteristics and not assume that an increase in satisfaction leads to decrease in dissatisfaction. The two-factor theory developed from data collected by Herzberg from interviews with 203 engineers and accountants in the Pittsburgh area, chosen because of their professions' growing importance in the business world. Regarding the collection process:  From analyzing these interviews, he found that job characteristics related to what an individual "does" — that is, to the nature of the work one performs — apparently have the capacity to gratify such needs as achievement, competency, status, personal worth, and self-realization, thus making him happy and satisfied. However, the "absence" of such gratifying job characteristics does not appear to lead to unhappiness and dissatisfaction. Instead, dissatisfaction results from unfavorable assessments of such job-related factors as company policies, supervision, technical problems, salary, interpersonal relations on the job, and working conditions. Thus, if management wishes to increase satisfaction on the job, it should be concerned with the nature of the work itself — the opportunities it presents for gaining status, assuming responsibility, and for achieving self-realization.