Maslow's Hierarchy of Needs Theory proposes that human needs are arranged in a hierarchy, from basic physiological needs at the bottom to self-actualization needs at the top. Clayton Alderfer built on this by developing the ERG theory of motivation, which categorizes human needs into Existence, Relatedness, and Growth. Frederick Herzberg also studied motivation and proposed his two-factor theory distinguishing between motivators and hygiene factors.

1. Maslow's Hierarchy of Needs Theory
Abraham Maslow was a social psychologist who was interested in a broad spectrum of human
psychological needs rather than on individual psychological problems. He is best known
for his hierarchy-of-needs theory.Maslow believed that these needs are similar to instincts
and play a major role in motivating behavior.

2. ALDERFER THEORY OF MOTIVATION
Clayton Alderfer developed Maslow’s Hierarchy of Needs into a three factor model of
motivation know as the ERG model. In this model the letter E, R, & G each stand for a different
human need: existence, relatedness and growth. The ERG model is a content theory of
motivation.

3. Herzberg