Degree Of Kinship Determines How Far We Are Willing To Travel To See Our Relatives

The woods are lovely, dark and deep,

But I have promises to keep,

And miles to go before I sleep,

And miles to go before I sleep.

Robert Frost - Stopping by Woods on a Snowy Evening

Maintaining regular face-to-face contact with family members can be rather challenging because nowadays families are often geographically dispersed. It takes time, money and effort to travel and visit family members. The famous British anthropologist and evolutionary psychologist Robin Dunbar at Oxford University and his colleagues investigated how far people were willing to travel to see their relatives. Their results were published in the open access journal PLOS One “Going That Extra Mile: Individuals Travel Further to Maintain Face-to-Face Contact with Highly Related Kin than with Less Related Kin” by Thomas Pollet et al. (online publication January 25, 2013). They asked 355 German and Dutch participants about the amount of travel time they invested to see their relatives that were not living with them in the same house. They classified the relatives by the degree of genetic relatedness. Siblings, parents and children of the participants were all combined in the first category (i.e. the ones that were most genetically related to the participants), half-siblings, aunts, uncles and grand-parents were in the second category and even more distant relatives such as cousins and half-cousins were in the third and fourth categories of genetic relatedness. The participants were also asked to comment about the degree of emotional closeness that they felt with the relatives that they visited. Travel time was used instead of distance, because we generally have an easier time making accurate estimates of how long it takes to make a trip than to estimate the actual number of traveled distances.

As expected, the researchers found that individuals were willing to travel for longer to see more closely related relatives than distantly related relatives. The second finding was that for all relatives in categories 2, 3 and 4 (i.e. aunts, uncles, grand-parents, cousins, nieces, half-siblings, second cousins, etc), emotional closeness determined how much travel time the participants were willing to invest. This means that participants were more likely to make a bigger effort to visit an emotionally close second cousin than a grandparent with whom they did not feel that strong of an emotional bond, even though grandparents were genetically closer. One of the most interesting findings of the study was that genetic relatedness to kin in the first category (parents, siblings and children) still trumped emotional closeness. Individuals were still willing to travel significantly further to see their closest relatives as compared to any other relatives, independent of the emotional closeness that they felt.

The study has some key limitations, such as the fact that it only included Dutch and German participants and these results may not apply to other societies or cultures. The sample size was also rather small and the researchers excluded adopted kin, because less than 2.5% of relatives were listed in this category. This did not allow the researchers to investigate whether the increased willingness to invest in travel time was truly due to genetic closeness, or whether perhaps participants would have put in just as much effort to see an adopted child who was not at all genetically related to them. Nevertheless, this study has interesting implications for understanding how we make decisions about investing time and effort into maintaining family relationships. It suggests that emotional closeness and friendship may be far more important determinants of our behavior for distant relatives than for close relatives.

Image credit: Wikimedia -17th century painting of a ship in the Brooklyn Museum Asian Art Collection, unknown artist

Pollet, T., Roberts, S., & Dunbar, R. (2013). Going That Extra Mile: Individuals Travel Further to Maintain Face-to-Face Contact with Highly Related Kin than with Less Related Kin PLoS ONE, 8 (1) DOI: 10.1371/journal.pone.0053929