This document discusses several theories related to circumstances under which pay increases motivate employees. It first discusses that pay increases can provide satisfaction to employees and motivate them to work on tasks they have little interest in. It then reviews several motivation theories including Maslow's hierarchy of needs, Herzberg's two-factor theory, Alderfer's ERG theory, McClelland's need for achievement theory, Adams' equity theory, Locke's goal setting theory, and Vroom's expectancy theory. The document concludes that according to these theories, there are several circumstances discussed in which increasing employee pay can lead to motivation, such as after working at a company for over three years during an economic recovery.