In sociology, the functionalist perspective examines how society’s parts operate. According to functionalism, different aspects of society exist because they serve a vital purpose. What is the function of social stratification? In 1945, sociologists Kingsley Davis and Wilbert Moore published the Davis-Moore thesis, which argued that the greater the functional importance of a social role, the greater must be the reward. The theory posits that social stratification represents the inherently unequal value of different work. Certain tasks in society are more valuable than others (for example, doctors or lawyers). Qualified people who fill those positions are rewarded more than others. According to Davis and Moore, a firefighter’s job is more important than, for instance, a grocery store cashier’s job. The cashier position does not require similar skill and training level as firefighting. Without the incentive of higher pay, better benefits, and increased respect, why would someone be willing to rush into burning buildings? If pay levels were the same, the firefighter might as well work as a grocery store cashier and avoid the risk of firefighting. Davis and Moore believed that rewarding more important work with higher levels of income, prestige, and power encourages people to work harder and longer. Davis and Moore stated that, in most cases, the degree of skill required for a job determines that job’s importance. They noted that the more skill required for a job, the fewer qualified people there would be to do that job. Certain jobs, such as cleaning hallways or answering phones, do not require much skill. Therefore, most people would be qualified for these positions. Other work, like designing a highway system or delivering a baby, requires immense skill limiting the number of people qualified to take on this type of work. Many scholars have criticized the Davis-Moore thesis. In 1953, Melvin Tumin argued that it does not explain inequalities in the education system or inequalities due to race or gender. Tumin believed social stratification prevented qualified people from attempting to fill roles (Tumin 1953).