In 1943, American psychologist Abraham Maslow proposed that all humans seek to fulfill a hierarchy of needs, which he represented with a pyramid. The pyramid’s base, which he believed must come first, signified basic needs (for food, sleep and sex, for example). Safety and security came next, in Maslow’s view, then love and belonging, then esteem and, finally, at the pyramid’s peak, a quality he called “self-actualization.” Maslow wrote that people who have these needs fulfilled should be happier than those who don’t.

In a new study, researchers at the University of Illinois put Maslow’s ideas to the test with data from 123 countries representing every major region of the world.

“Anyone who has ever completed a psychology class has heard of Abraham Maslow and his theory of needs,” said University of Illinois professor emeritus of psychology Ed Diener, who led the study. “But the nagging question has always been: Where is the proof? Students learn the theory, but scientific research backing this theory is rarely mentioned.”

The researchers turned to the Gallup World Poll, which conducted surveys in 155 countries from 2005 to 2010, and included questions about money, food, shelter, safety, social support, feeling respected, being self-directed, having a sense of mastery, and the experience of positive or negative emotions. Diener, a senior scientist for the Gallup Organization, helped design the survey.

he researchers found that fulfillment of a diversity of needs, as defined by Maslow, do appear to be universal and important to individual happiness. But the order in which “higher” and “lower” needs are met has little bearing on how much they contribute to life satisfaction and enjoyment, Diener said.

They also found that the fulfillment of more basic needs – for money, food or shelter, for example – was more closely linked to a positive life evaluation, the way an individual ranked his or her life on a scale from worst to best. The satisfaction of higher needs – for social support, respect, autonomy or mastery – was “more strongly related to enjoying life – having more positive feelings and less negative feelings,” Diener said.

An important finding, Diener said, is that the research indicated that people have higher life evaluations when others in society also have their needs fulfilled.

“Thus life satisfaction is not just an individual affair, but depends substantially also on the quality of life of one’s fellow citizens,” he said.

“Our findings suggest that Maslow’s theory is largely correct. In cultures all over the world the fulfillment of his proposed needs correlates with happiness,” Diener said. “However, an important departure from Maslow’s theory is that we found that a person can report having good social relationships and self-actualization even if their basic needs and safety needs are not completely fulfilled.”

“Another revision of his theory is that we found that different needs produce different types of well-being,” Diener said.