Men are naturally better navigators than women, right? It’s a pervasive assumption that has become deeply ingrained in Western thinking. But it may not be completely true. According to a new and comprehensive study, there is good reason to doubt that any apparent difference between the wayfinding abilities of males and females is due to natural selection. In short, if there are differences, then it has nothing to do with men having evolved to be better.
Existing research has focused on spatial cognition, where hundreds of studies, and a few meta-analyses, have accumulated results that can be summed as this: males outperform females in a statistically significant way in multiple spatial tasks and to varying degrees.
The idea is pretty popular, the authors explain. “The tendency to explain sex differences as products of natural selection is especially common in evolutionary psychology, where there is a long-standing preoccupation with cognitive sex differences.”
The standard explanation, known as the sex-specific adaptation hypothesis, explains this by comparison to other species, especially those where the males have larger home size ranges (the size of the area an animal travels in during its daily activities) than females. In these instances, it is assumed that males experience more selection for wayfinding skills than females.
To test this explanatory hypothesis, US researchers from various organizations examined the differences in wayfinding in 21 different species, including humans, and compared the sizes of their home ranges.
Some of the animals they examined included Asian small-clawed otters, brilliant-thighed poison frogs, Californian mice, chimpanzees, rats, horses, giant pandas, and various species of voles.
The results revealed very little evidence of sex differences in home range size that correlated with how well each species navigated.
"Over the past half-century, significant resources have gone into testing the sex-specific adaptation hypothesis as an explanation for sex differences in navigation abilities," the authors wrote. "In a previous meta-analysis, we found the evidence was weak, and in this paper with an expanded dataset, we again find little evidence supporting the sex-specific adaptation hypothesis."
Sex differences in behavior or performance can arise from biological or cultural factors, neither of which necessarily stem from evolution in all instances. In particular, the brain’s plasticity means it's particularly good at restructuring, a factor that is often ignored.
In particular, evolutionary psychologists consider a trait as innate if it is culturally universal, but that does not hold with spatial skills.
“Recent evidence in subsistence populations strongly suggests that sex difference in spatial navigation in humans is not a cultural universal”, the authors explain. “Rather, it disappears in cultures where males and females have similar ranging behaviour.”
“We believe that future research on human sex differences in navigation should focus on the role of socialization and culture, rather than evolutionary genetic factors.”
The paper is published in Royal Society Open Science.