This is published in PLOS ONE.
Wagnild J, Wall-Scheffler CM (2013) Energetic Consequences of Human Sociality: Walking Speed Choices among Friendly Dyads. PLoS ONE 8(10): e76576. doi:10.1371/journal.pone.0076576
I am still trying trying to decide whether this work is incredibly profound or incredibly trivial.
The authors conclude that “When walking with female romantic partners, males tend to slow down by about 7%,”. They claim that “these findings could have implications for both mobility and reproductive strategies of groups, and could help interpret fossil footprint trails and hunter gatherer strategies”.
Their results.
- Partners: Male Partners had faster preferred speeds when walking alone (average: 1.53 ms−1) than the Female Partners (average: 1.44 ms−1; p = 0.05). When Male and Female Partners walked together, the Male Partners significantly slowed their paces in order to walk with their Female Partners (average: 1.44 ms−1; p = 0.009). When asked to hold hands while walking with their Partner, the Male Partners slowed their paces further (average: 1.43 ms−1; p = 0.007). The walking speed of the Female Partners only slightly changed when walking with the Male Partners, with or without hand-holding.
- Opposite Sex Friends: When the Female Partners walked with the Male Friends, the Female Partners increased their speeds (from 1.44 ms−1 to 1.48 ms−1; 2.8%; p = 0.410) while the Male Friends decreased their speeds (from 1.52 ms−1 to 1.48 ms−1; 2.6%; p = 0.255), thus demonstrating a compromise of speeds. Similarly, when the Male Partners walked with the Female Friends, the Female Friends increased their speeds (from 1.41 ms−1 to 1.47 ms−1; 4.3%; p = 0.391) while the Male Partners decreased their speeds (from 1.53 ms−1 to 1.47 ms−1; 4.0%; p = 0.146), again demonstrating a compromise of speeds. In summary, when males and females who were not romantically involved walked together, there was not a significant difference in either’s walking speeds away from solo walking. Males did not significantly slow their speeds to walk with females who were their Friend, though their speed choice did decrease slightly.
- Same Sex Friends: When Male Partners walked with Male Friends, walking speeds were faster than either individual’s preferred walking speed (4%; p = 0.716 for Male Partners and p = 0.595 for Male Friends). When Female Partners walked with Female Friends, walking speeds were slower than either individual’s preferred speed (3%; p = 0.351 for Female Partners and p = 0.571 for Female Friends)
From their Discussion:
….. The data do show however, that there is a decrease in the speed choice between males walking alone and males walking with females; the degree of this speed “accommodation,” however, is linked to the relationship status of the male-female pair, such that males will nearly match the females’ paces only if they are in a romantic relationship. In friendships, the male slows down, but to a lesser (non significant) degree. Furthermore, the differences found between male-male dyads and female-female dyads are also consistent with the hypothesis that social closeness will be mirrored by speed choices. ……. In recent hunter-gatherer populations, males and females often travel similar distances making the energetic consequences of daily mobility an important selection pressure on both sexes. When people of both sexes walk together, either both sexes must pay an energetic penalty by compromising speeds (as seen in the Partner-Friend dyad) or the male must pay an energetic penalty to accommodate the female’s speed (as seen in the Partner-Partner dyad). To alleviate this energetic penalty, many populations travel in single-sex groups in which males travel alone or in pairs and females travel together ……
So I suppose I should conclude that when hunter-gatherers moved from one place to another, the men went first, the women followed and romantic couples followed last – whether holding hands or not?
EurekAlert:
When walking with female romantic partners, males tend to slow down by about 7%, according to new research published Oct 23 in the open-access journal PLOS ONE, by Cara Wall-Scheffler and colleagues at Seattle Pacific University.
People have an optimal walking speed that minimizes energy expenditure. This optimal speed varies with physical features like mass and lower limb length, and therefore males in any given population tend to have faster optimal walking speeds than females. Given this difference, it is not clear what happens in walking groups of mixed-sex. In order to walk together, someone in the pair will need to pay the energetic cost of deviating from his or her optimal speed.
The authors here examined individuals’ speed choices when they walked around a track alone, with a significant other (with and without holding hands), and with friends of the same and opposite sex. They found that males walk at a significantly slower pace to match the females’ paces, only when the female is their romantic partner. The paces of friends of either same or mixed sex walking together did not significantly change, suggesting that significant pace adjustments occur only for romantic partners.
These findings could have implications for both mobility and reproductive strategies of groups, and could help interpret fossil footprint trails and hunter gatherer strategies.
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