How many friends do you have?


ResearchBlogging.orgPollet, T., Roberts, S., & Dunbar, R. (2011). Use of Social Network Sites and Instant Messaging Does Not Lead to Increased Offline Social Network Size, or to Emotionally Closer Relationships with Offline Network Members Cyberpsychology, Behavior, and Social Networking, 14 (4), 253-258 DOI: 10.1089/cyber.2010.0161

I recently happened to read this new article (access here). Its main interest is that it is part of two broader debates on, respectively, the size of personal networks and the impact of online communication on socialisation.

Let us first start with the size of personal networks. A milestone in this debate is the so-called “Dunbar’s number“, based on a 1992 study of one of the co-authors of the above mentioned article. The idea (laid out with caution by its proponent, but taken literally by those who followed as usually happens) is that human cognitive capacities as measured by the size of the neocortex lead to a network size of 148 (rounded to 150). The original study compared the size of the neocortex in various groups of primates and humans and referred to cohesive communities.  The resulting limit indicates the number of people with whom one can maintain “stable” social relationships, i.e., know who each alter is, and how alters are related to one another.
Other numbers have been proposed: in a series of articles between 1990 and 2001, Peter Killworth and co-authors found a mean personal network size of 290 (which doubles the Dunbar number); more recently, Matthew Salganik and his co-authors (2010) have come up with an even larger size of 610, which in turn doubles Killworth’s number.
Other parts of the brain may be involved too, suggest neuroscientists: Lisa Barrett and her co-authors (2010) found a correlation between amygdala volume and social network size in humans. (Though I’m not an expert,  the amygdala is the part of brain that regulates emotional responses and aggression, while the neocortex to which Dunbar referred is the part of the brain that presides higher mental functions.) (see this Blogpost for further information).
In social network analysis perspective, it is also important to define which social network we are dealing with. Peter Marsden (1987) distinguished “core” networks from whole personal networks à la Dunbar, pointing out that even when people have many friends, there are only a handful with whom they “can discuss important matters”. On the other hand, full networks may be instead larger than Dunbar’s, which does not include mere acquaintances or weaker ties; measures of full networks taken by Killworth and co-authors went up to about 1500 for the average American.
Overall, an issue that emerges from many of these discussions is that cognitive capacities (however defined) matter primarily because they are associated with a basic limitation of all living beings –time is finite and what’s more, limited. Therefore, increasing the size of one’s personal network implies that less time is available for each alter: the size of the overall network increases, but the size of the core network doesn’t. Weak ties may gain at the expense of strong ties.
Let’s now look at the debate on the socializing or de-socializing effects of computer-mediated communication. In a controversial article on the  “Internet paradox” (1998), Robert Kraut and co-authors suggested that the more time users devote to web-based interactions, the more they lose contact with family and close friends. In this perspective, the Web would exacerbate the trade-off between weak ties (supposedly online) and strong ones (supposedly offline). Yet the authors themselves came to more nuanced conclusions a few years later, with their “The Internet paradox revisited” (2002) in which they admitted that what they observed was probably a temporary effect, and that it varied significantly with individual characteristics (gender, age etc.). Subsequent studies, starting from those of Barry Wellman (2002), have rather tended to emphasize how Internet is a complementary form of socialization; recently, a growing body of results have stressed the positive effects of the  Web especially for persons for whom socialization is  challenging (those with illnesses for example). (see this Blogpost for further information).
But just for curiosity, how many friends do people actually have online? The Economist reports that in a 2009 study of Facebook, Cameron Marlow found that the average is around 120 (though it can go up to 500+, and is slightly higher for women than men). In practice, however, people communicate with less alters: men leave comments for 7 friends and women for 10; by email or chat, men communicate with 4, women with 6 friends.
Now, how does the article in question contribute to these debates? Basically, it asks whether Social Networking Services (SNS) and Instant Messaging (IM) increase personal network size; and whether they increase overall strength of ties. The answer to both questions is NO.
Interesting aspects of this article are that it defines personal networks as sets of three concentric circles, which it labels the support, sympathy, and active networks, depending on two key variables: frequency of contacts and degree of perceived emotional closeness. The sample includes mainly students (as often happens in psychology studies) but not only students (good!); and the question of time and cognitive constraints is explicitly posed. It is said, in particular, that constancy of network size is largely due to limited leisure time.
One question that arises, then, is whether networking is just leisure -or can it result from a mix of leisure and professional motivations? Dalton Conley has proposed the notion of  “weisure” (2009) to indicate a societal shift towards activities that combine work and leisure (including social networking with colleagues who are also friends). The organisational literature suggests that social networking may yield distinct career advantages (Burt 1992, 2005).  I wonder, then, what would happen with a sample of respondents who are mainly professionals rather than students  and may be doing an investment in view of a reward: would we find a larger network size and/or stronger ties?
Another important issue is the distinction between the different layers of a social network -is frequency of contact really important? How related is it with perceived emotional closeness? Would a population of migrants who have   sporadic contacts with their families of origin due to costs or communication difficulties, feel less close to them? Again, replicating the study with different populations of respondents may raise different challenges and perhaps lead to different results.
A broader issue is the degree of overlap between offline and online networks -a lot of research is being done at the moment on this topic, but further work is certainly necessary.
A lot to think about… and all in all, we still don’t know how many friends we have.
References are available here.

3 Responses to “How many friends do you have?”

  1. Wonderful post. It’s THE question that a lot of people have. Especially business professionals. For organisations it’s interesting to have some insight in the potentially useable social capital.

  2. A new article has just come out (25 May 2011) in arxiv to validate Dunbar’s number using data on Twitter conversations:

  1. 1 How many friends do you have? | Data Big and Small

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