Maslow's hierarchy of needs is a theory in psychology, proposed by Abraham Maslow in his 1943 paper "A Theory of Human Motivation." Maslow subsequently extended the idea to include his observations of humans' innate curiosity. His theories parallel many other theories of human developmental psychology, all of which focus on describing the stages of growth in humans. Maslow use the terms Physiological, Safety, Belongingness and Love, Esteem, and Self-Actualization needs to describe the pattern that human motivations generally move through.

Hierarchy

Maslow's hierarchy of needs is often portrayed in the shape of a pyramid, with the largest and most fundamental levels of needs at the bottom, and the need for self-actualization at the top. While the pyramid has become the de facto way to represent the hierarchy, Maslow himself never used a pyramid to describe these levels in any of his writings on the subject.

The most fundamental and basic four layers of the pyramid contain what Maslow called "deficiency needs" or "d-needs": esteem, friendship and love, security, and physical needs. With the exception of the most fundamental (physiological) needs, if these "deficiency needs" are not met, the body gives no physical indication but the individual feels anxious and tense. Maslow's theory suggests that the most basic level of needs must be met before the individual will strongly desire (or focus motivation upon) the secondary or higher level needs. Maslow also coined the term Metamotivation to describe the motivation of people who go beyond the scope of the basic needs and strive for constant betterment. Metamotivated people are driven by B-needs (Being Needs), instead of deficiency needs (D-Needs).

The human mind and brain are complex and have parallel processes running at the same time, so many different motivations from different levels of Maslow's pyramid usually occur at the same time. Maslow was clear about speaking of these levels and their satisfaction in terms such as "relative" and "general" and "primarily", and says that the human organism is "dominated" by a certain need, rather than saying that the individual is "only" focused on a certain need at any given time. So Maslow acknowledges that many different levels of motivation are likely to be going on in a human all at once. His focus in discussing the hierarchy was to identify the basic types of motivations, and the order that they generally progress as lower needs are reasonably well met.

(source: en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs)