Maslow posited that human needs could be placed in a pyramid with the most basic physiological or biological needs -- such as those for nutrients and water and safety at the bottom and self-actualization at the top. Only if lower-level or "deficit" needs are met can higher level needs such as those for belonging and esteem be addressed. The highest level was variously called self-actualization or "being" needs. Maslow estimated that only 2 percent of the population is able to address this need.
Fromm wrote sweeping historical works criticizing the nature of society and its inability to meet human needs. According to Fromm, basic needs include the need for relatedness, transcendence, rootedness, identity and a frame of orientation. Humans are motivated to produce useful items. Fromm critiques modern society in comparison to the medieval era because it has become hard to meet the need to create.
Murray created the TAT or thematic apperception test to identify unconscious motivations in human personality. Murray complied a list of 27 human motivations from the biological to the psychogenic. Murray saw motivation to meet these needs as the key to human personality. Some of the needs identified by Murray include the need for dominance, aggression, acceptance, affiliation and achievement. Murray stated that a need plus a "press" or external pressure to meet a need led to motivation.
One of many more recent psychologists interested in the development of a psychology of positive states of being, Dr. Yukio Ishizuka worked to quantify well-being. Examining only psychological needs and motives, Ishizuka divided human motives into three spheres: the search for self, the need for intimacy and the quest for achievement. Recurring themes of the need for interaction, self-understanding and meaningful work underlie the work of psychologists in understanding what truly motivates humans.