What do alterations in canoe design in Polynesia have to do with evolution? They offer a clear-cut example of how natural selection can influence cultural change, argue the authors of a paper published in March in Proceedings of the National Academy of Sciences.
The researchers studied the design of canoes from Fiji and 10 Polynesian island cultures. They looked at the history of functional design changes: modifications that affect the seaworthiness of the boat, such as the design of the hull or the attachment of the outriggers. They also noted alterations in the canoes’ symbolic elements, decorations that have no functional purpose.
The authors hypothesized that functional elements, tested against the environment, could provide a survival advantage, while decorations would not. Therefore, these two kinds of traits should change at different rates.
The hypothesis proved correct. Statistical analysis showed that over a period of 2,500 to 3,000 years, functional traits across the cultures changed much more slowly than decorative designs, suggesting that those functional elements were subject to the pressure of natural selection, probably through differences in fishing yields, in the safety of the boats’ occupants, and especially in success at colonization. In other words, beneficial cultural traits—those that provide a survival advantage—persist in the same way as do beneficial genetic traits.
“People need to realize that the cultural choices they make have a significant bearing on outcomes for humans, individuals, families, and cultures,” says Deborah Rogers, lead author of the study and a graduate research fellow at Stanford University. “We can make any choice we want, but we will face the consequences.”