This article in Wired covers new research on networks and information by Sinan Aral (Northwestern B.A. in Political Science, MIT Sloan PhD, now at NYU Stern) and Marshall Van Alstyne. The article describes research on the email communications of members of an executive recruiting firm, and says, “those who relied on a tight cluster of homophilic contacts received more novel information per unit of time.” The article is confusing though because it mixes several distinct network concepts: homophily, strong ties, clustering, and “band width.” Homophily is the tendency for people to be connected to other people that are similar to them; birds of a feather flock together. In his seminal paper, “The Strength of Weak Ties,” Mark Granovetter defined the strength of a tie as “a (probably linear) combination of the amount of time, the emotional intensity, the intimacy (mutual confiding), and the reciprocal services which characterize the tie”. Clustering measures the tendency of our friends to be friends with each other. And bandwidth is a less standard term in the social networks literature that captures the total amount of information that flows through a given tie per unit time (and thus is about the same thing as strength of a tie).
After reading the Wired piece, I’m left wondering if it is
- strong or “high bandwidth” ties through which we communicate a lot of total information,
- homophilic ties with people that are similar to us,
- ties with people that are members of a tightly knit cluster of friends, or
- all of the above
that provide us with the most novelty in our information diet.
A look at the original research article makes it more clear why the Wired article was so confusing. The actual argument has a lot of moving pieces to it. The first argument is that structurally diverse networks tend to have lower bandwidth ties. Here structurally diverse appears to mean not highly clustered. So, you talk more to the people in your personal clique than to people outside of your tightly knit group. The second piece relates structural diversity to information diversity. They find that the more structurally diverse the network, the more diverse the information that flows through it. So far, this seems to line up with the standard Granovetter weak ties story. The third relationship is that increasing bandwidth also increases information diversity, and more importantly, increasing bandwidth increases the total volume of new (non-redundant) information that an individual receives. The idea here is that if you get tons of information from someone, some of it is going to be new.
Finally, since both structural diversity and bandwidth increase information diversity, but structural diversity decreases with increased bandwidth, they set up a head to head battle to see whether the information diversity benefits of increasing bandwidth outweigh the costs of reducing structural diversity. They have three main findings on this front that characterize when bandwidth is beneficial:
- “All else equal, we expect that the greater the information overlap among alters, the less valuable structural diversity will be in providing access to novel information.”
- “All else equal, the broader the topic space, the more valuable channel bandwidth will be in providing access to novel information.”
- “All else equal, ... the higher the refresh rate, the more valuable channel bandwidth will be in providing access to novel information.”