started building company buildings with a limit of 150 employees and only 150 parking spaces. When the parking spaces were filled, the company would build another 150-employee building. Sometimes these buildings would be placed only short distances apart. The number has been used in the study of virtual communities, especially MMORPGs, such as Ultima Online, and social networking websites, such as Facebook (Dunbar himself did a study on Facebook in 2010) and MySpace. The Swedish tax authority planned to reorganise its functions in 2007 with a maximum 150 employees per office, referring to Dunbar's research. In 2007, Cracked.com editor David Wong wrote a humour piece titled "What is the Monkeysphere?" explaining Dunbar's number and its implications. In his 2012 novel This Book Is Full of Spiders, the character Marconi explains to David the effect Dunbar's number has on human society. In Marconi's explanation, the limit Dunbar's number imposes on the individual explains phenomena such as racism and xenophobia, as well as apathy towards the suffering of peoples outside of an individual's community. In a piece for the Financial Times (10 August 2018) titled 'Why drink is the secret to humanity's success," Dunbar mentioned two more numbers: an inner core of about 5 people to whom we devote about 40 percent of our available social time and 10 more people to whom we devote another 20 percent. All in all, we devote about two-thirds of our time to just 15 people. In episode 103 of the podcast Hello Internet (31 May 2018) Brady Haran and CGP Grey discuss the reasons the number may be limited to 150, including the ability to keep track of political relationships in large groups of people and the amount of time that people have to devote towards developing and maintaining friendships. In the 2020 novel The Midnight Library by Matt Haig, the character Ash references Dunbar's number, explaining that "humans are only capable of 150 social connections." See also Size of groups, organizations, and communities References Further reading External links "The ultimate brain teaser" – an article on Dunbar's research at University of Liverpool Research Intelligence The Dunbar Number as a Limit to Group Sizes by Christopher Allen – applying Dunbar's number to on-line gaming, social software, collaboration, trust, security, privacy, and internet tools, by Christopher Allen Robin Dunbar: How Many Friends Does One Person Need? Fora.TV talk at the RSA Evolutionary psychology Interpersonal relationships Human