Six Degrees of Separation Theory

Aug 6, 2025

Overview

This lecture discusses the "Six Degrees of Separation" theory, its origins, and how modern social networking has shortened the degrees between people.

Origins of Six Degrees of Separation

  • The "Six Degrees of Separation" theory suggests anyone is at most six steps away from any other person.
  • Stanley Milgram, a social psychologist, coined the phrase after the 1967 "small world experiment."
  • Milgram's experiment involved mailing a package from the US West Coast to a Boston stockbroker through acquaintances.
  • The average number of steps needed was six in Milgram’s original study.

Impact of Modern Social Networks

  • Social platforms like LinkedIn use connection labels (2nd, 3rd connections) to show degrees of separation.
  • Facebook shows mutual friends and allows messaging with friends of friends if enough connections exist.
  • Social networking sites make these degrees more visible and easier to navigate.

Research on Degrees in the 21st Century

  • A 2011 study by Facebook and the University of Milan analyzed 721 million users and 69 billion friendships.
  • 99.6% of users were connected by paths within five degrees.
  • 92% of users were separated by only four degrees.
  • The average distance between all people on Facebook dropped from 5.28 (2008) to 4.74 (2011).

Key Terms & Definitions

  • Six Degrees of Separation — The idea that everyone is connected by a chain of six or fewer acquaintances.
  • Small World Experiment — Milgram’s study testing how many steps it took for a package to reach a target via acquaintances.
  • Degree of Separation — The number of direct or indirect social connections linking two people.

Action Items / Next Steps

  • Reflect on how social networking might further reduce degrees of separation.
  • Consider how your own online connections demonstrate this theory.