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Cultural Change Reduces Gender Differences in Mobility and Spatial Ability among Seminomadic Pastoralist-Forager Children in Northern Namibia

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Abstract

A fundamental cognitive function found across a wide range of species and necessary for survival is the ability to navigate complex environments. It has been suggested that mobility may play an important role in the development of spatial skills. Despite evolutionary arguments offering logical explanations for why sex/gender differences in spatial abilities and mobility might exist, thus far there has been limited sampling from nonindustrialized and subsistence-based societies. This lack of sampling diversity has left many unanswered questions regarding the effects that environmental variation and cultural norms may have in shaping mobility patterns during childhood and the development of spatial competencies that may be associated with it. Here we examine variation in mobility (through GPS tracking and interviews), performance on large-scale spatial skills (i.e., navigational ability), and performance on small-scale spatial skills (e.g., mental rotation task, Corsi blocks task, and water-level task) among Twa forager/pastoralist children whose daily lives have been dramatically altered since settlement and the introduction of government-funded boarding schools. Unlike in previous findings among Twa adults, boys and girls (N = 88; aged 6–18) show similar patterns of travel on all measures of mobility. We also find no significant differences in spatial task performance by gender for large- or small-scale spatial skills. Further, children performed as well as adults did on mental rotation, and they outperformed adults on the water-level task. We discuss how children’s early learning environments may influence the development of both large- and small-scale spatial skills.

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  1. Some studies have found a gender difference in mental rotation (or its precursors) in preschoolers and even infancy (Levine et al. 1999; Moore and Johnson 2011; Quinn and Liben 2014), although preschoolers often fail at this task (Frick et al. 2013, 2014).

References

  • Baenninger, M., & Newcombe, N. (1989). The role of experience in spatial test performance: A meta-analysis. Sex Roles, 20(5), 327–344

    Article  Google Scholar 

  • Berry, J. B. (1966). Temne and Eskimo perceptual skills. International Journal of Psychology, 1(3), 207–229.

    Article  Google Scholar 

  • Bates, D., Mächler, M., Bolker, B., & Walker, S. (2015). Fitting linear mixed-effects models using lme4. Journal of Statistical Software, 67(1), 1–48. https://doi.org/10.18637/jss.v067.i01.

    Article  Google Scholar 

  • Blüchel, M., Lehmann, J., Kellner, J., & Jansen, P. (2013). The improvement in mental rotation performance in primary-school-aged children after a two-week motor-training. Educational Psychology, 33(1), 75–86.

  • Bock, J., & Sellen, D. W. (2002). Childhood and the evolution of the human life course. Human Nature, 13(2), 153–159.

    Article  Google Scholar 

  • Bollig, M. (2004). Hunters, foragers, and singing smiths: The metamorphoses of peripatetic peoples in Africa. In J. C. Berland & A. Rao (Eds.), Customary strangers: New perspectives on peripatetic peoples in the Middle East, Africa, and Asia (pp. 195–231). Westport, CT: Praeger.

  • Bryant, K. J. (1982). Personality correlates of sense of direction and geographic orientation. Journal of Personality and Social Psychology, 43(6), 1318–1324.

    Article  Google Scholar 

  • Bürkner, P. (2016). Package ‘brms’. https://github.com/paul-buerkner/brms.

  • Cashdan, E., & Gaulin, S. J. C. (2016). Why go there? Evolution of mobility and spatial cognition in women and men. Human Nature, 27(1), 1–15.

    Article  Google Scholar 

  • Cashdan, E., Marlowe, F. W., Crittenden, A., Porter, C., & Wood, B. M. (2012). Sex differences in spatial cognition among Hadza foragers. Evolution and Human Behavior, 33(4), 274–284.

    Article  Google Scholar 

  • Chavajay, P. (2006). How Mayan mothers with different amounts of schooling organize a problem-solving discussion with children. International Journal of Behavioral Development, 30(4), 371–382.

    Article  Google Scholar 

  • Dasen, P. R., Mishra, R., and Niraula, S. (2004). The influence of schooling on cognitive development: A review of research in India. In B. N. Setiadi, A. Supratiknya, W. J. Lonner, and Y. H. Poortinga (Eds.), Ongoing themes in psychology and culture: Proceedings from the 16th International Congress of the International Association for Cross-Cultural Psychology. https://scholarworks.gvsu.edu/iaccp_papers/261.

  • Davis, H. E. (2014). Variable education exposure and cognitive task performance among the Tsimane forager-horticulturalists. PhD dissertation, University of New Mexico.

  • Davis, H. E., & Cashdan, E. (2019). Spatial cognition, navigation, and mobility among children in a forager-horticulturalist population, the Tsimané of Bolivia. Cognitive Development, 52, 100800.

    Article  Google Scholar 

  • Davis, H. E., and Cashdan, E. (2020). You don’t have to know where your kids are, just where they aren’t: Exploring free-range parenting in the Bolivian Amazon. In B. K. Ashdown & A. N. Faherty (Eds.), Parents and caregivers across cultures (pp. 59–74). Springer International.

  • Davis, H. E., Stieglitz, J., Kaplan, H., & Gurven, M. (2020). Poor school quality augments differences in children's abstract reasoning over time. https://psyarxiv.com/d3sgq/.

  • Doyle, R. A., Voyer, D., & Cherney, I. D. (2012). The relation between childhood spatial activities and spatial abilities in adulthood. Journal of Applied Developmental Psychology, 33(2), 112–120.

    Article  Google Scholar 

  • Draper, P. (1976). Social and economic constraints on child life among the !Kung. Anthropology Faculty Publications, 13. https://doi.org/10.4159/harvard.9780674430600.c16.

  • Draper, P., & Cashdan, E. (1988). Technological change and child behavior among the !Kung. Ethnology, 27(4), 339–365.

    Article  Google Scholar 

  • Ecuyer-Dab, I., & Robert, M. (2004). Spatial ability and home-range size: Examining the relationship in Western men and women (Homo sapiens). Journal of Comparative Psychology, 118(2), 217–231.

    Article  Google Scholar 

  • Edwards, C. P. (2000). Children’s play in cross-cultural perspective: A new look at the six cultures study. Cross-Cultural Research, 34(4), 318–338.

    Article  Google Scholar 

  • Edwards, C. P., & Whiting, B. B. (1980). Differential socialization of girls and boys in light of cross-cultural research. New Directions for Child and Adolescent Development, 1980(8), 45–57.

    Article  Google Scholar 

  • Endicott, K. M., & Endicott, K. L. (2008). The headman was a woman: The gender egalitarian Batek of Malaysia (Vol. 1). Denver: Waveland.

    Google Scholar 

  • Estermann, C. (1981). The ethnography of southwestern Angola: The Herero people (translated and edited by Gibson GD). New York: Africana Publishing.

    Google Scholar 

  • Flannery, R. (1953). The Gros Ventres of Montana: Part 1, social life. Washington DC: Catholic University of America Press.

    Google Scholar 

  • Forbes, E. E., & Dahl, R. E. (2010). Pubertal development and behavior: Hormonal activation of social and motivational tendencies. Brain and Cognition, 72(1), 66–72.

    Article  Google Scholar 

  • Fox, J., Weisberg, S., Adler, D., Bates, D., Baud-Bovy, G., Ellison, S., Firth, D., Friendly, M., Gorjanc, G., and Graves, S. (2012). Package ‘car.’ Vienna: R Foundation for Statistical Computing.

  • Frick, A., Hansen, M. A., & Newcombe, N. S. (2013). Development of mental rotation in 3- to 5-year-old children. Cognitive Development, 28(4), 386–399.

    Article  Google Scholar 

  • Frick, A., Möhring, W., & Newcombe, N. S. (2014). Development of mental transformation abilities. Trends in Cognitive Sciences, 18(10), 536–542.

    Article  Google Scholar 

  • Galea, L. A. M., & Kimura, D. (1993). Sex differences in route-learning. Personality and Individual Differences, 14(1), 53–65.

  • Gallois, S., Duda, R., Hewlett, B. S., & Reyes-García, V. (2015). Children’s daily activities and knowledge acquisition: A case study among the Baka from southeastern Cameroon. Journal of Ethnobiology and Ethnomedicine, 11, 86. https://doi.org/10.1186/s13002-015-0072-9.

  • Gaulin, S. J. C., & FitzGerald, R. W. (1986). Sex differences in spatial ability: An evolutionary hypothesis and test. American Naturalist, 127(1), 74–88.

  • Gaulin, S. J., FitzGerald, R. W., & Wartell, M. S. (1990). Sex differences in spatial ability and activity in two vole species (Microtus ochrogaster and M. pennsylvanicus). Journal of Comparative Psychology, 104(1), 88–93.

    Article  Google Scholar 

  • Geary, D. C. (1995). Sexual selection and sex differences in spatial cognition. Learning and Individual Differences, 7(4), 289–301.

    Article  Google Scholar 

  • Gramann, K., Hoepner, P., & Karrer-Gauss, K. (2017). Modified navigation instructions for spatial navigation assistance systems lead to incidental spatial learning. Frontiers in Psychology, 8, 193.

    Article  Google Scholar 

  • Gurven, M., Fuerstenberg, E., Trumble, B., Stieglitz, J., Beheim, B., Davis, H. E., & Kaplan, H. (2017). Cognitive performance across the life course of Bolivian forager-farmers with limited schooling. Developmental Psychology, 53(1), 160–176.

    Article  Google Scholar 

  • Hart, R. (1979). Children’s experience of place. New York: Irvington.

    Google Scholar 

  • Hegarty, M. (2018). Ability and sex differences in spatial thinking: What does the mental rotation test really measure? Psychonomic Bulletin and Review, 25(3), 1212–1219.

    Article  Google Scholar 

  • Hegarty, M., and Waller, D. (2005). Individual differences in spatial abilities. In Priti Shah and Akira Miyake (eds.), The Cambridge Handbook of Visuospatial Thinking, 121–169. Cambridge: Cambridge University press.

  • Hegarty, M., Montello, D. R., Richardson, A. E., Ishikawa, T., & Lovelace, K. (2006). Spatial abilities at different scales: Individual differences in aptitude-test performance and spatial-layout learning. Intelligence, 34(2), 151–176.

    Article  Google Scholar 

  • Henrich, J., Heine, S. J., & Norenzayan, A. (2010). The weirdest people in the world? The Behavioral and Brain Sciences, 33(2–3), 61–83 83–135.

    Article  Google Scholar 

  • Henrie, R. L., Aron, R. H., Nelson, B. D., & Poole, D. A. (1997). Gender-related knowledge variations within geography. Sex Roles, 36(9), 605–623.

    Article  Google Scholar 

  • Hlavac, M. (2018). Stargazer: Well-formatted regression and summary statistics tables. R Package version 5.2.2. https://CRAN.R-project.org/package=stargazer.

  • Hoffman, M., Gneezy, U., & List, J. A. (2011). Nurture affects gender differences in spatial abilities. Proceedings of the National Academy of Sciences, 108(36), 14786–14788.

    Article  Google Scholar 

  • Hox, J. J., van de Schoot, R., & Matthijsse, S. (2012). How few countries will do? Comparative survey analysis from a Bayesian perspective. Survey Research Methods, 6(2), 87–93.

    Google Scholar 

  • Jang, H., Boesch, C., Mundry, R., Kandza, V., & Janmaat, K. R. (2019). Sun, age and test location affect spatial orientation in human foragers in rainforests. Proceedings of the Royal Society B, 286(1907), 20190934.

    Article  Google Scholar 

  • JASP Team. (2020). JASP version 0.13.1. https://jasp-stats.org/.

  • Jeffreys, H. (1998). The theory of probability. Oxford: Oxford University Press.

    Google Scholar 

  • Jones, C. M., Braithwaite, V. A., & Healy, S. D. (2003). The evolution of sex differences in spatial ability. Behavioral Neuroscience, 3, 403–411.

    Article  Google Scholar 

  • Jozet-Alves, C., Modéran, J., & Dickel, L. (2008). Sex differences in spatial cognition in an invertebrate: The cuttlefish. Proceedings of the Royal Society B: Biological Sciences, 275(1646), 2049–2054.

    Article  Google Scholar 

  • Kleinfeld, J. (1971). Visual memory in village Eskimo and urban Caucasian children. Arctic, 24(2), 132–138.

    Article  Google Scholar 

  • Kessels, R. P., Van Zandvoort, M. J., Postma, A., Kappelle, L. J., & De Haan, E. H. (2000). The Corsi block-tapping task: Standardization and normative data. Applied Neuropsychology, 7(4), 252–258.

    Article  Google Scholar 

  • Lancy, D. F. (2014). The anthropology of childhood: Cherubs, chattel, changelings. Cambridge: Cambridge University Press.

    Book  Google Scholar 

  • Lee, S.-Y., & Song, X.-Y. (2004). Evaluation of the Bayesian and maximum likelihood approaches in analyzing structural equation models with small sample sizes. Multivariate Behavioral Research, 39(4), 653–686.

    Article  Google Scholar 

  • Levine, S. C., Huttenlocher, J., Taylor, A., & Langrock, A. (1999). Early sex differences in spatial skill. Developmental Psychology, 35(4), 940–949.

    Article  Google Scholar 

  • Li, C. (2000). Instruction effect and developmental levels: A study on water-level task with Chinese children ages 9–17. Contemporary Educational Psychology, 25(4), 488–498.

    Article  Google Scholar 

  • Li, C., Nuttall, R. L., & Zhao, S. (1999). A test of the Piagetian water-level task with Chinese students. The Journal of Genetic Psychology, 160(3), 369–380.

    Article  Google Scholar 

  • Li, J. (2014). The effect of the assumed boundary in the solving of the nine-dot problem on a sample of Chinese and American students 6–18 years old. PhD dissertation. University of Massachusetts-Amherst.

  • Linn, M. C., & Petersen, A. C. (1985). Emergence and characterization of sex differences in spatial ability: A meta-analysis. Child Development, 56(6), 1479–1498.

    Article  Google Scholar 

  • Malan, J. S. (1974). The Herero-speaking peoples of Kaokoland. Cimbebasia (B), 2, 113–129.

  • Malinowski, J. C. (2001). Mental rotation and real-world wayfinding. Perceptual and Motor Skills, 92(1), 19–30.

    Article  Google Scholar 

  • Matthews, M. H. (1987). Gender, home range and environmental cognition. Transactions of the Institute of British Geographers, n.s. 12, 43–56. https://doi.org/10.2307/622576.

  • McElreath, R. (2020). Statistical rethinking: A Bayesian course with examples in R and Stan. Boca Raton: CRC Press.

  • Moore, D. S., & Johnson, S. P. (2011). Mental rotation of dynamic, three-dimensional stimuli by 3-month-old infants. Infancy, 4, 435–445.

    Article  Google Scholar 

  • Munroe, R. L., & Munroe, R. H. (1971). Effect of environmental experience on spatial ability in an East African society. The Journal of Social Psychology, 83(1), 15–22.

  • Nazareth, A., Huang, X., Voyer, D., & Newcombe, N. (2019). A meta-analysis of sex differences in human navigation skills. Psychonomic Bulletin and Review, 26(5), 1503–1528.

    Article  Google Scholar 

  • Nerlove, S. B., Munroe, R. H., & Munroe, R. L. (1971). Effect of environmental experience on spatial ability: A replication. The Journal of Social Psychology, 84(1), 3–10.

    Article  Google Scholar 

  • Neuburger, S., Jansen, P., Heil, M., & Quaiser-Pohl, C. (2011). Gender differences in pre-adolescents’ mental-rotation performance: Do they depend on grade and stimulus type? Personality and Individual Differences, 50(8), 1238–1242.

    Article  Google Scholar 

  • O’Hara, R., and Kotze, J. (2010). Do not log-transform count data. Nature Precedings. https://doi.org/10.1038/npre.2010.4136.1.

  • Piaget, J., & Szeminska, A. (1941). La genèse du nombre chez l’enfant. Neuchatel & Paris: Delachaux & Niestle.

    Google Scholar 

  • Price-Williams, D., Gordon, W., & Ramirez, M. (1969). Skill and conservation: A study of pottery-making children. Developmental Psychology, 1(6, part 1), 769.

    Article  Google Scholar 

  • Quinn, P. C., & Liben, L. S. (2014). A sex difference in mental rotation in infants: Convergent evidence. Infancy, 19(1), 103–116.

    Article  Google Scholar 

  • Rissotto, A., & Tonucci, F. (2002). Freedom of movement and environmental knowledge in elementary school children. Journal of Environmental Psychology, 22(1), 65–77.

    Article  Google Scholar 

  • Ruginski, I. T., Creem-Regehr, S. H., Stefanucci, J. K., & Cashdan, E. (2019). GPS use negatively affects environmental learning through spatial transformation abilities. Journal of Environmental Psychology, 64, 12–20.

    Article  Google Scholar 

  • Salthouse, T. A. (2006). Mental exercise and mental aging: Evaluating the validity of the “use it or lose it” hypothesis. Perspectives on Psychological Science, 1(1), 68–87.

    Article  Google Scholar 

  • Schielzeth, H. (2010). Simple means to improve the interpretability of regression coefficients. Methods in Ecology and Evolution, 1(2), 103–113.

    Article  Google Scholar 

  • Schönbrodt, F. D., & Wagenmakers, E.-J. (2018). Bayes factor design analysis: Planning for compelling evidence. Psychonomic Bulletin and Review, 25(1), 128–142.

    Article  Google Scholar 

  • Seng, A. S. H., and Tan, L. C. (2002). Cultural and gender differences in spatial ability of young children. Paper presented at the annual meeting of the Association for Childhood Education, San Diego, CA.

  • Silverman, I., Choi, J., and Peters, M. (2007). The hunter-gatherer theory of sex differences in spatial abilities: Data from 40 countries. Archives of Sexual Behavior, 2(261–268).

  • Silverman, I., Choi, J., Mackewn, A., Fisher, M., Moro, J., & Olshansky, E. (2000). Evolved mechanisms underlying wayfinding: Further studies on the hunter-gatherer theory of spatial sex differences. Evolution and Human Behavior, 21(3), 201–213.

    Article  Google Scholar 

  • Stan Development Team. (2020). RStan: The R interface to Stan. http://mc-stan.org/.

  • Stieglitz, J., Gurven, M., Kaplan, H., & Hooper, P. L. (2013). Household task delegation among high-fertility forager-horticulturalists of lowland Bolivia. Current Anthropology, 54(2), 232–241.

    Article  Google Scholar 

  • Thomas, H., & Turner, G. F. (1991). Individual differences and development in water-level task performance. Journal of Experimental Child Psychology, 51(2), 171–194.

    Article  Google Scholar 

  • UNICEF. (2013). Regional education analysis for Namibia. Windhoek: UNICEF.

    Google Scholar 

  • Uttal, D. H., Meadow, N. G., Tipton, E., Hand, L. L., Alden, A. R., Warren, C., & Newcombe, N. S. (2013). The malleability of spatial skills: A meta-analysis of training studies. Psychological Bulletin, 139(2), 352–402. https://doi.org/10.1037/a0028446.

    Article  Google Scholar 

  • VanMeerten, N., Varma, K., Gravelle, M., Miller, N., Kraikul, E., & Fatemi, F. (2019). Evidence of a relationship between mental rotation skills and performance in a 3D puzzle game. Frontiers in Education, 4, 82. https://doi.org/10.3389/feduc.2019.00082.

    Article  Google Scholar 

  • Vashro, L. (2014). Residence and childcare assistance among the Twe. PhD dissertation, University of Utah.

  • Vashro, L. (2015). The search for additional mating opportunities helps explain larger ranges of Twe men. Paper presented at the annual conference of the Human Behavior and Evolution Society, May 26, Columbia, MO.

  • Vashro, L., & Cashdan, E. (2015). Spatial cognition, mobility, and reproductive success in northwestern Namibia. Evolution and Human Behavior, 36(2), 123–129.

    Article  Google Scholar 

  • Vashro, L., Padilla, L., & Cashdan, E. (2016). Sex differences in mobility and spatial cognition. Human Nature, 27(1), 16–34.

    Article  Google Scholar 

  • Voyer, D., Voyer, S., & Bryden, M. P. (1995). Magnitude of sex differences in spatial abilities: A meta-analysis and consideration of critical variables. Psychological Bulletin, 117(2), 250–270.

    Article  Google Scholar 

  • Wagenmakers, E.-J., Marsman, M., Jamil, T., Ly, A., Verhagen, J., Love, J., Selker, R., Gronau, Q. F., Šmíra, M., & Epskamp, S. (2018). Bayesian inference for psychology. Part I: Theoretical advantages and practical ramifications. Psychonomic Bulletin and Review, 25(1), 35–57.

    Article  Google Scholar 

  • Wallace, E., and Hoebel, E. A. (1952). The Comanches: Lords of the South Plains. University of Oklahoma Press.

  • Webley, P. (1981). Sex differences in home range and cognitive maps in eight-year-old children. Journal of Environmental Psychology, 1(4), 293–302.

  • Weisner, T. S. (2002). Ecocultural understanding of children’s developmental pathways. Human Development, 45(4), 275–281.

    Article  Google Scholar 

  • Whiting, B., & Edwards, C. P. (1973). A cross-cultural analysis of sex differences in the behavior of children aged three through 11. The Journal of Social Psychology, 91(2), 171–188.

    Article  Google Scholar 

  • Whiting, B. B., & Edwards, C. P. (1992). Children of different worlds: The formation of social behavior. Cambridge: Harvard University Press.

    Google Scholar 

  • Whiting, B. B., & Whiting, J. W. (1975). Children of six cultures: A psycho-cultural analysis. Cambridge: Harvard University Press.

    Book  Google Scholar 

  • Wickham, H. (2010). ggplot2: Elegant graphics for data analysis (use R!). New York: Springer.

    Google Scholar 

  • Wolbers, T., & Hegarty, M. (2010). What determines our navigational abilities? Trends in Cognitive Sciences, 14(3), 138–146.

    Article  Google Scholar 

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Acknowledgments

We thank John Jakurama for his continued assistance on the project. We also thank the members of the University of Utah’s Spatial Cognition and Navigation (SCAN) Project for invaluable insight and feedback, as well as Phoebe McNeally and the DIGIT lab for assistance with GIS data. Finally, we would like to thank Layne Vashro, Chelsea Leonard, Ronelle and Lorens Rademeyer, and Jason Leiser for logistical support throughout the duration of this study. This study was funded by NSF grant BCS 1628583.

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All analyses, figures, and tables were conducted in R-3.6.2 and LaTeX2e. Code is available upon request.

Funding

This project was supported by the National Science Foundation NSF (BCS 1628583).

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  1. Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA

    Helen E. Davis

  2. One Pencil Project, 501(c)(3), Salt Lake City, UT, USA

    Jonathan Stack

  3. Department of Anthropology, University of Utah, Salt Lake City, UT, 84112, USA

    Elizabeth Cashdan

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EC designed research; JS and HD performed research; HD analyzed data; HD and EC wrote the paper.

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Correspondence to Helen E. Davis.

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Davis, H.E., Stack, J. & Cashdan, E. Cultural Change Reduces Gender Differences in Mobility and Spatial Ability among Seminomadic Pastoralist-Forager Children in Northern Namibia. Hum Nat 32, 178–206 (2021). https://doi.org/10.1007/s12110-021-09388-7

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