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Why Go There? Evolution of Mobility and Spatial Cognition in Women and Men

An Introduction to the Special Issue

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Abstract

Males in many non-monogamous species have larger ranges than females do, a sex difference that has been well documented for decades and seems to be an aspect of male mating competition. Until recently, parallel data for humans have been mostly anecdotal and qualitative, but this is now changing as human behavioral ecologists turn their attention to matters of individual mobility. Sex differences in spatial cognition were among the first accepted psychological sex differences and, like differences in ranging behavior, are documented for a growing set of species. This special issue is dedicated to exploring the possible adaptive links between these cognitive and ranging traits. Multiple hypotheses, at various levels of analysis, are considered. At the functional (ultimate) level, a mating-competition hypothesis suggests that range expansion may augment mating opportunities, and a fertility-and-parental-care hypothesis suggests that range contraction may facilitate offspring provisioning. At a more mechanistic (proximate) level, differences in cue availability may support or inhibit particular sex-specific navigation strategies, and spatial anxiety may usefully inhibit travel that would not justify its costs. Studies in four different cultures—Twe, Tsimane, Yucatec Maya, and Faroese—as well as an experimental study using virtual reality tools are the venue for testing these hypotheses. Our hope is to stimulate more research on the evolutionary and developmental processes responsible for this suite of linked behavioral and cognitive traits.

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Notes

  1. Using published data from 11 species, Clint et al. (2012) undertook a cross-species test of the hypothesized relationship between mobility and spatial ability and claimed to find no relationship. Of course the power of this test was low, but more importantly, 4 of the 11 cases—all high-leverage data points (see their Fig. 2b)—may be misinterpreted. These 4 cases are briefly discussed below.

    Two species (feral horses and rhesus macaques) are alleged to undermine the hypothesis because they show sex differences in spatial ability but lack sex differences in home range size. It is true that social groups move as units so that there will never be sex differences in range size within a social group. But to take the hypothesis seriously one must ask whether one sex travels farther in the formation of these groups. Rhesus macaque females very rarely leave their natal groups, but males emigrate from their natal groups shortly before puberty and may continue to change groups throughout their lives in search of mating opportunities (Melnick et al. 1984a, b). In horses, both sexes disperse from the natal group, but males actively seek and herd females to form harems (Cameron et al. 2009; Kaseda et al. 1997; Linklater et al. 1999), though a quantitative assessment of lifetime ranges is not currently available. Of these two cases, then, macaques actually support the range-size hypothesis and horses are at worst inconclusive.

    Two more species—the cuttlefish (Sepia officinalis) and a tucu-tucu (Ctenomys talarum)—supposedly undermine the hypothesis from the other side, showing sex differences in ranging behavior but lacking sex differences in spatial ability. Regarding the first of these species Clint et al. cite an article by Jozet-Alves et al. (2008) with the title “Sex Differences in Spatial Cognition in an Invertebrate: The Cuttlefish” in which the authors conclude: “Our data are consistent with the predictions of the range size hypothesis (Gaulin and FitzGerald 1986, 1989): a difference in range expansion between males and females is associated with a difference in spatial learning abilities” (Jozet-Alves et al. 2008:2052). Regarding the second, the cited source (Mastrangelo et al. 2010) explicitly notes that spatial ability was assessed outside the breeding season. That renders these data irrelevant since, even in species well documented to show the predicted range size-spatial ability relationship, sex differences in both range size and spatial ability disappear outside the breeding season (Galea et al. 1994, 1996; Gaulin and FitzGerald 1988). Thus, of this second pair of species, one species supports rather than undermines the hypothesized relationship between mobility and spatial ability. For the other species the data are inconclusive and should not have been construed as relevant evidence.

    Without these four species (or with rhesus macaques and cuttlefish properly placed), their Fig. 2b shows the expected positive relationship between range size and spatial ability, and this relationship would have been even stronger had Clint et al. cited an article by Perdue et al. (2011), who explicitly tested the range-size hypothesis and also found the expected relationship using data on two other, closely related carnivore species.

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  1. Department of Anthropology, University of Utah, Salt Lake City, UT, USA

    Elizabeth Cashdan

  2. Department of Anthropology, University of California, Santa Barbara, CA, USA

    Steven J. C. Gaulin

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Cashdan, E., Gaulin, S.J.C. Why Go There? Evolution of Mobility and Spatial Cognition in Women and Men. Hum Nat 27, 1–15 (2016). https://doi.org/10.1007/s12110-015-9253-4

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