Clayton Alderfer

Clayton Paul Alderfer (September 1, 1940 - October 30, 2015)[1] was an American psychologist and consultant known for developing Abraham Maslow's hierarchy of needs into a framework of three essential categories: existence, relatedness, and growth.

In 1977 he also obtained certification from the American Board of Professional Psychology (ABPP).

After graduation, Alderfer started his academic career at Cornell University in 1966.

In 1968 he returned to Yale University, where he was researcher, lecturer and program director in the Department of Administrative Sciences until 1992.

[citation needed] Alderfer developed Maslow's hierarchy of needs into a framework consisting of three essential categories: existence, relatedness, and growth (ERG theory).