A new study suggests that we lose and replace about half of our friends every seven years, and as a result the size of our social network remains the same over time.
For ages sociologists have debated whether personal preference or social context holds more sway over how we meet people and the nature of our relationships (would, for example, your husband have become your husband if you’d met him in a bar instead of via your best friend?). Sociologist Gerald Mollenhorst took on the challenge of addressing this question by crafting a study that investigated how the context in which we meet people influences our social network.
Mollenhorst conducted a survey of 1007 people ages 18 to 65 years. Seven years later the respondents were contacted once again and 604 people were reinterviewed. They answered questions such as: Who do you talk with regarding important personal issues? Who helps you with projects in your home? Who do you pop by to see? Where did you get to know that person? And where do you meet that person now?
The results: personal network sizes remained stable, but many members of the network were new. Only 30 percent of the original ‘helper’ friends and discussion partners had the same position in a subject’s network seven years later, and only 48 percent were still part of the social network. This finding contradicts previous research showing that social network sizes are shrinking because we are becoming increasingly individualistic. Evidently, not so much.
Mollenhorst also found that social networks were not formed based on personal choices alone. Our choice of friends is limited by opportunities to meet, and people often choose friends from a context in which they have previously chosen a friend. If the pond had fish the first time, why not cast back in?
Also, in contrast to research that suggests people typically separate things like work, social clubs and friends, this study shows that these categories often overlap – another blow to the argument that we’re becoming staunch individualists who keep our social compartments separate.
David DiSalvo is a freelance writer and research wonk who has written and lectured on topics involving public health, air and water quality, branding, education, energy efficiency, healthcare and social marketing. More info 
8 Comments
June 4, 2009 at 4:15 am
Ive lost many friends
June 4, 2009 at 7:08 am
This is interesting. On a personal level I feel a little less guilty about drifting away from some friends, but on a broader level I am reminded of some research that found Facebook users have social networks that are the same size as non-users… can’t remember the details right now. It seems that social network size is not something easily affected by conditions.
It makes me curious what the heritability of social network size might be. Are there any studies on that?
June 9, 2009 at 4:12 pm
I don’t understand the bit about individualism. I consider myself a raging individualist, but hello, I still have friends! lol I don’t see how individualism relates to friendship in the ways they were thinking. I expect my friends to respect my individualism, and I respect theirs.
June 9, 2009 at 6:45 pm
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June 9, 2009 at 9:18 pm
Super interesting. Helps me justify my old tendency of dismissing friends along with petty arguments or miscommunications that may have ensued (which may not have been a good thing but apparently its normal lol)
June 16, 2009 at 4:35 pm
[...] number of friends doesn’t change much over our lifetime. The bad news? We’re fickle. A new study suggests that we lose and replace about half of our friends every seven years. (Time to check your [...]
June 22, 2009 at 8:06 pm
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September 8, 2009 at 12:02 pm
[...] The seven-year itch cuts our friends in half — personal network sizes remained stable, but many members of the network were new — [...]