Maslow’s need hierar- chy theory and Alderfer’s existence, relatedness, and growth (ERG) theory, sug- gest that needs are arranged in a hierarchy.49 They propose that needs emerge in a particular pattern whereby certain groups of needs (those important to physical survival) emerge first and must be satisfied before other needs (psychological and social, like affiliation and esteem) can emerge and affect behavior. Once currently activated needs are satisfied, the next most powerful group of needs is felt and will then drive behavior.
Maslow’s need hierarchy lists five categories (or levels) of needs: physiological, safety and security, love, status and esteem, and self-actualization. Alderfer’s ERG theory reduces Maslow’s hierarchy to three levels of needs: existence, relat- edness, and growth. More importantly, ERG theory proposes that if a person becomes frustrated trying to satisfy currently activated needs, this frustration causes previously satisfied needs to activate and drive behavior.