邓巴数

邓巴系数（），也稱150定律，指能與某個人維持緊密人際關係的人數上限，通常人們認為是150。这里的人际关系是指某个人知道其他人是谁并且了解那些人之间的关系。支持者认为超过这个人数上限的团队，需要更加严格的规则，法律以及强制性规范来维持稳定性和凝聚力（）。鄧巴數並沒有精確的數值，它處於100到230之間，而通常人們使用150。邓巴数首先是英国的人类学家罗宾·邓巴於1990年代提出，是新皮质的大小决定的，并因此成为了一个团队规模的限制。新皮质处理能力决定了能与某个人维持紧密人际关系的人数上限。在這樣的團體中，每個人都認識彼此且知道彼此的關係。此外，这个数量包括熟悉的老同学和老同事，也就是說實際的親密的朋友數量會更少，直至接近個位數。

参考文献
外部連結

• [https://web.archive.org/web/20051211031726/http://www.liv.ac.uk/researchintelligence/issue17/brainteaser.html "The ultimate brain teaser"] – an article on Dunbar's research at University of Liverpool Research Intelligence
• [https://web.archive.org/web/20051214141613/http://mythical.blogspot.com/2004_06_01_mythical_archive.html Some speculations about a correlation between the monkeysphere and guild size in online multiplayer role-playing games]
• [http://www.lifewithalacrity.com/2004/03/the_dunbar_numb.html 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
• [https://web.archive.org/web/20141202004603/http://fora.tv/2010/02/18/Robin_Dunbar_How_Many_Friends_Does_One_Person_Need Robin Dunbar: How Many Friends Does One Person Need?] Fora.TV talk at the RSA
• [http://www.cracked.com/article_14990_what-monkeysphere.html What is the Monkeysphere?] By David Wong at Cracked