This five-stage model can be divided into deficiency needs and growth needs. The first four levels are often referred to as deficiency needs (D-needs), and the top level is known as growth or being needs (B-needs).
Deficiency needs arise due to deprivation and are said to motivate people when they are unmet. Also, the motivation to fulfill such needs will become stronger the longer the duration they are denied. For example, the longer a person goes without food, the more hungry they will become.
Maslow (1943) initially stated that individuals must satisfy lower level deficit needs before progressing on to meet higher level growth needs. However, he later clarified that satisfaction of a needs is not an “all-or-none” phenomenon, admitting that his earlier statements may have given “the false impression that a need must be satisfied 100 percent before the next need emerges”