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.