Virtually all of the published evaluations showed Marlow's pyramid of needs is invalid, including studies conducted by Maslow's friends sympathetic to his ideas. To put it simply, the pyramid does not exist.
Maslow made these mistakes:
1. Maslow's categories are invalid. Maslow classified orderliness, for example, as a safety need, but it isn't. Orderliness is an intrinsic need for sameness; it is not an effort to manage anxiety. Maslow did not accurately identify nor scientifically validate a list of human needs. He had no idea how needs relate to each other because he conducted almost no relevant studies.
2. Maslow's sequence is invalid. There is no progression of human development in adults along the lines he suggested. Maslow's idea that esteem needs represent higher development than belonging needs, for example, is contradicted by scientific research. Achievement needs, for example, are evident in early adolescence
and, if strong, tend to stay strong throughout adult life. They do not go up and down in priorization as the pyramid suggests.
3. Maslow erred in suggesting a one size fits all heriarchy of human needs. We now know each individual prioritizes needs differently from others. We have assessed the needs of more than 50,000 people on three continents using scientific tools. Everybody has their own heirarchy and it is stable from age 12 to age 60.
Maslow's hierarchy does not exist. People do not go from focusing one one set of needs to focusing on a different set of needs. Generally, the strength of all needs rises throughout the adolescent years and peaks around ages 25-35. Young people become passionate about most everything, not just a segment of the pyramid. After that it is mostly downhill as the intensity of the needs decline. Old people lose passion for most everything.
An individual's prioritizations of needs is stable throughout the adult years. It corresponds to the individual's values and personality
, not to the individual's human development. Although all desires are rising in adolescence and falling with advancing age, the relative prioritizations, and thus the person's values, are steady.
I recommend Maslow's work for the construct of self-actualization, which is a deep and interesting idea. Philosophers and theologians have been pondering human transcendence for centuries, and Maslow offered a novel perspective. The rest of Maslow's work, especially the hierarchy, is simply not true. Maslow should be read as a philosopher of human nature, not as a scientist concerned with data and validity.