Alderfer's Modified Need Hierarcy Model (ERG Theory)

Alderfer gives a variation of Maslow's need theory and refers to his version as the ERG model of motivation. Alderfer condenses Maslow's five levels of needs into three levels based on the core needs of existence, relatedness, and growth.

Existence Needs are concerned with sustaining human existence and survival and cover Maslow's physiological and safety needs. They include all the various forms of material desires such as food, water, pay and good working conditions.

Relatedness Needs are concerned with relationships to the social environment and cover love, belonging, affiliation and meaningful interpersonal relationships of a safety or esteem nature.Growth Needs are concerned with the development of potential and cover esteem and self actualization.
       
Note:

The difference between Alderfer's and Maslow's theory is deeper than just in the number of levels.Alderfer does not exactly see the needs as a heirarchy but he finds that one class of needs might remain strong, whether or not another class has been satisfied. But ideally he (like Maslow) suggests that individuals progress from existence needs, to relatedness, to growth needs as the lower level needs become satisfied.

•    He suggests that more than one need (level) may be activated at the same time.
•   He also suggests (unlike Maslow) that individuals do progress down the hierarchy e.g. for a person who has been continually frustrated in attempting to satisfy growth needs, relatedness needs may assume most importance.

Alderder had certain propositions:

1.    The less existence needs are satisfied the more they will be desired (like Maslow).
2.    The less relatedness needs are satisfied the more existence needs will be desired (disagrees with Maslow).
3.    The less relatedness needs are satisfied the more they will be desired (agrees with Maslow).
4.    The less growth needs are satisfied, the more relatedness needs will be desired (unlike Maslow).

By simplifying the class of needs Alderfer is subject to less misunderstanding. The result of Alderfers work suggest that lower level needs do not need to be satisfied before higher level needs emerge as motivators (unlike Maslow). His theory however agrees with Maslow in as far as that lower needs decrease in strength as they become satisfied.