The content theories of motivation focus on the factors within the person that energize, direct, sustain, and stop behavior. They attempt to determine the specific needs that motivate people. Four important content approaches to motivation are (1) Maslow's need hierarchy, (2) Alderfer's ERG theory, (3) Herzberg's two-factor theory, and (4) McClelland's learned needs theory. Each of these four theories has had an impact on managerial practices and will be considered in the paragraphs that follow.