The reliability of Six-Degree & the effects of Connection

Kadushin explained about the concept of "Six Degrees of Separation". He argues that "For most purposes, the number of effectively consequential zones is between two and three; that is, whatever is being studied, individuals or organizations, past the third or at most fourth zone objects or nodes have relatively small effects on the focal individual or structure."(p.11) I want to consider the reliability of "Six-Degree" and the question that "Does the connections with the people, past the third or fourth zones, have only small effects?"


According to http://ja.wikipedia.org/wiki/%E5%85%AD%E6%AC%A1%E3%81%AE%E9%9A%94%E3%81%9F%E3%82%8A this Web page (sorry, its Japanese), if six people, who have the connections with 43.15 people, are connected, every people on the earth will be connected because 43.15 to the 6th power (the 6th root of 43.15?) is 6,454,829,873... and the world population in 2005 is 6,453,581,351, which is less than 43.15 to the 6th power. Of course, it does not consider the overlaps, so this number can not be true. Moreover, if there is any person who is not connected with anyone, nobody can reach him or her. Therefore, it is almost impossible to connect all people on the earth through six people. However, if you give up those who are connected with nobody, there is still possibility to connect other people. I don't know what is the enough number of connections to overcome those overlaps, but 43.15 is a quite small number. If connections are not restricted to only strong ones, most people should have more than 43.15 connections. I can't prove this theory to be right, but considering the number 43.15, I think it seems to be probable.


To answer the question that "Does the connections with the people, past the third or fourth zones, have only small effects?" , the strength of connections must be defined. In here, I suppose that being connected means that knowing each other. If so, I don't think the effect of connections will decrease as the number of the zones increases. Each zone should have almost same effects. For example, if you want to ask something people in the sixth zone know, first you will ask someone in the first zone. You and the person in the first zone know each other, so he or she is likely to ask your favor. Next, the person in the first zone will ask the person in the second zone. The probability that the person in the second zone will do his or her favor is same as the case between you and the person in the first zone. It will not change. Therefore, the effects of connections cannot be changed by the number of zones. Of course, the speed to get the information you want will change, but at least, you can get the information you want.


I'm sorry to write redundant blog. Thank you for your patience.



Bibliography

Charles, Kadushin. Introduction to Social Network Theory. Unknown, 2003.