The Dunbar Number refers to the cognitive limit to the number of social relationships that humans can maintain at any given time. This number has been found to be approximately 150 in different studies, which has been coined the "Dunbar Number". This concept was first theorized by British anthropologist Robin Dunbar and is based on the amount of neocortical processing capability available, along with the amount of time and effort required to maintain these relationships. The Dunbar Number is neither fixed nor absolute, and can vary based on cultural context, but serves as a helpful concept to understand the limits of human social interaction.

See also: collective intelligence, collective action, human nature