Construction of Networking Game for Addressing Social Isolation in a Super-Aging Society - Innovative Management in Information and Production - page 346

3.2 Strength of Weak Ties

The “strength of weak ties” is part of a social network theory that holds that
weak networks (weak ties), such as nonintimate friends or “friends of friends,”
are actually more important than strong networks (strong ties), such as families,
intimate friends, or colleagues, in transferring valuable information or innovation.
This hypothesis was proposed in 1973 by American sociologist Mark Granovetter
in his paper “Strength of weak ties” ( Research Report on Preventing Social Isolation
of Elderly 2012 ), which reported on his empirical study seeking to identify a
job-matching mechanism between companies and workers. The study, conducted
in 1970, involving 282 male white-color workers in Newton City, a suburb of
Boston, found that 56 % had found their jobs through human networks and that,
of these, those who had found their jobs based on information obtained through
weak human networks were more satisfied with their jobs. This is because much
of the information obtained through strong networks that included the job seekers
themselves was already known to them, while much of that obtained through weak
networks was both unknown to them and important.
Granovetter claims that weak ties act as a “bridge” to connect strong networks,
playing a critical role in transferring information to extensive areas. Networks
consisting of strong ties have high levels of homogeneity and similarity and a
tendency to concentrate only on strong ties, leading eventually to isolation of the
network. Weak ties are required to promote mutual understanding and the transfer
of information.
Much of the information and knowledge transferred through weak ties are
valuable to the recipients. People are typically in frequent contact within strong
networks but in many cases exchange only mediocre information. People in
weak networks, on the other hand, tend to exchange more important information,
precisely because their weak relationships make only that sort of information worth
exchanging.

3.3 Network Invariants

We must be careful in inserting shortcuts to lessen the distance within a network, as
special, arbitrarily added weak ties could shrink its world. All we require is a small
number of long-distance links or hubs with an extremely large number of links.
Such a simple fact can build small-world networks in every context, including
the varied human relationships that bond us with society, or languages used in
conversation or thought.
Watts formulated two network invariants ( Milgram 1967 ). One is the average
length of the shortest path between all the pairs of joints L, as shown in Fig. 5 a.
The other is the cluster coefficient C , which may be defined as follows: