Maslow's hierarchy of needs is a theory in psychology proposed by Abraham Maslow in his 1943 paper "A Theory of Human Motivation" in Psychological Review. According to Maslow, human beings have two basic sets of needs that are rooted in their biology: deficiency (or basic) needs, and growth (or meta) needs.

Maslow's Hierarchy of Human Needs
Posted by Psychology Learners on Sunday, 19 July 2015

Basic Needs

From most to least powerful, the basic needs are:
1. Physiological needs: includes hunger, thirst, sex etc. People deprived of food for long periods of time, for example, would begin to focus more and more of their attention on that deficiency.
2. Safety needs: includes needs for security, protection, structure, law, order, limits, and freedom from fear, anxiety, and chaos (Maslow, 1970a, p. 39). In Maslow’s view, the need for security manifests itself in infants and children when their environment is disturbed.
3. Needs for belongingness and love: tend to emerge once the physiological and safety needs are routinely met. Maslow argued that all of us need to feel wanted and accepted by others.
4. Esteem needs: He divided them into two sets: esteem based on respect for our own competence, independence, and accomplishments, and esteem based on others’ evaluations.

Meta Needs

Once the basic needs in Maslow’s hierarchy have been sufficiently gratified, the needs for self-actualization and cognitive understanding become salient. People seek to gratify their innate curiosity about themselves and the workings of the environment, to know and understand phenomena that go beyond the gratification of basic needs, to move toward realization of their own unique potentialities.

Evaluation of Theory 

The theory is evaluated in terms of six criteria:
1. Comprehensiveness: The focus is primarily and explicitly on the issue of positive growth rather than the Freudian model of Pathology, therefore, it is somewhat limited in the range and diversity of phenomena it encompasses.
2. Precision and testability : Maslow’s theory is not very precise and, as a result, is difficult to test properly. Ex: Exceptions in hierarchy not defined.
3. Parsimony:  The motivational deficiency scheme he used to account for various behaviors is too simplistic to account adequately for the phenomena within its domain.
4. Empirical validity: Without adequate measures of the major constructs in Maslow’s theory, tests of its empirical validity are impossible.
5. Heuristic value:  Maslow’s theory has been provocative and has stimulated the thinking of many investigators in a variety of disciplines.
6. Applied value:  His formulations have had a decided impact on pastoral and educational counseling programs. Many business managers have embraced his ideas.

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Maslow’s theory categorises human needs into two major types – Basic needs and Meta needs. Basic needs include physiological needs like food and sex, safety and security needs, belongingness and love needs and esteem needs. Meta needs include the need for self-actualisation – i.e, achieving one’s full potential. These needs are hierarchically ordered and only after a need at the lower level is satisfied can a need at the higher level be satisfied.

Sources:
http://figur8.net/baby/2014/11/06/maslows-hierarchy-of-needs-and-how-it-relates-to-your-childs-education/
https://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs
Theories of Personality, Richard M. Ryckman (Click for eBook)