The five major approaches that may led to our understanding of motivation are Maslow's need-hierarchy theory, Herzberg's two- factor theory, Vroom's expectancy theory, Adams' equity theory, and Skinner's reinforcement theory.
According to Maslow, employees have five levels of needs (Maslow, 1943): physiological, safety, social, ego, and self- actualizing. Maslow argued that lower level needs had to be satisfied before the next higher level need would motivate employees. Herzberg's work categorized motivation into two factors: motivators and hygienes (Herzberg, Mausner, & Snyderman, 1959). Motivator or intrinsic factors, such as achievement and recognition, produce job satisfaction. Hygiene or extrinsic factors, such as pay and job security, produce job dissatisfaction.
Vroom's theory is based on the belief that employee effort will lead to performance and performance will lead to rewards (Vroom, 1964). Rewards may be either positive or negative. The more positive the reward the more likely the employee will be highly motivated. Conversely, the more negative the reward the less likely the employee will be motivated.