148, or 150

  • suggested cognitive limit to the people with whom one can maintain social relationships with.
  • Proposed by Robert Dunbar, British anthropologist.
  • Found a link between primate brain size and average group size

Dunbar predicted a human “mean group size” of 148 (casually rounded to 150), a result he considered exploratory because of the large error measure (a 95% confidence interval of 100 to 230)