The Utility of a Social Network

Dora Costa and Matthew Kahn discuss some of the research on social networks, and they come up with the following nuggets:

• The most important factor to minimize desertion from companies in the Civil War was having a homogeneous unit, meaning similar types of people (I assume this means ethnic and geographically.)
• About 75% of men who joined the Salafi Jihad did so with their friends or family or because a close friend was already involved. Apparently the ideology was rationalized only later.
  
• Those who lack a social network (ie, self-report as socially isolated) have a higher risk of death from certain viruses, cancer, and heart disease. The explanation is that they have more stress.

What if all of your friends are joining a quasi-militant movement that you do not agree with? You must either conform or face serious consequences--not only emotionally but also physically.

Perhaps the ultimate utility of a wide social network is that you can always afford to let a few friends go their own way without taking too much of a hit.