The Small World Theory

The small world theory studies the average path lengths in social networks. The concept of the average path length in network topology involves calculating the number of steps along the shortest path between every possible pair of nodes in a network. This measurement involves the study of network theory where the information transfers and connection between nodes are examined. Any two individuals in a social network are likely to be connected though a short sequence of intermediate acquaintances. Short average path lengths are most desirable in networks.



In the 1960’s a social psychologist by the name of Stanley Milgram conducted the “small-world experiment”. His experiment suggests that the human society can be referred to as a ‘small world’ due to the short path lengths connecting any two individuals in the world. He conducted this experiment by tracing chain letters and investigating the short chains of acquaintances that connected a pair of strangers in the United States. Milgram discovered that a successful chain letter required five to six intermediary steps before reaching the desired destination. Today, Milgram’s principle is commonly referred to as “six degrees of separation”. This is a fundamental principle in social networks and emphasises the short paths that link any two people in the world who know one another.

Recent work has proposed that the small world phenomenon is omnipresent in networks that involve nature, technology and the underlying element in the structural advancement of the World Wide Web. The “Small World Research Project” investigates Milgram’s theory and additionally conducts research on the types of barriers that seem to divide the society; whether it concerns an individual’s characteristic such as age, race or level of education. Information, news and opinions continuously spread through the world wide social structure. The way a single piece of information spreads on a global scale has always been a mystery. This small world theory is ever more fascinating in the digital age.

References:
David Liben-Nowell and Jon Kleinberg (2008).
Tracing information flow on a global scale using Internet chain-letter data. (vol. 105, no.12)

Judith S. Kleinfeld (2002), Could it be a big world?.
From http://www.judithkleinfeld.com/ar_bigworld.html