Hunter-gatherer theory of spatial sex differences

1. Hunter-gatherer theory of spatial sex differences

2. Hunter-gatherer theory of spatial sex differences • Previous research has shown a male advantage in spatial tests, e.g., 3-dimensional rotations. • Conclusion: males have better spatial abilities than females. • Silverman & Eals 1992: males and females have different spatial competencies. • evolutionary theory: division of labor during the Pleistocene era whereby males functioned primarily as hunters, and females as gatherers of plant food. • So males should be good at orientation within a large and unpredictable environment. • And females should be good at learning the contents of object arrays and relationships within these arrays. • Males prefer orientation strategy, females prefer landmark strategy.

3. Silverman et al 2007 • Methods • Internet study (BBC) • 250,000 participants in 226 countries • Tests: • Object Location Memory (prediction F > M) • 3-D Mental Rotation (prediction M > F)

4. OLM Test

5. OLM Test

6. OLM Test

7. 3DMR Test

8. Silverman et al 2007

9. Farmers Market Study (New et al PRSL 2007)

10. Farmers Market Study (New et al PRSL 2007) • Participants recruited near entrance to FM • Told they could earn $10 (or $5 and UCSB tote bag) by participating in ‘farmers’ market research’ (their cover story, it does not refer to any spatial task) • Asked age and how frequently they visited FM (control variable), gender noted • Participant led by circuitous route to 6 food stalls, where they were given an item to eat. • At each stall, participants were asked a set list of questions which served to promote the cover story and were also analyzed as possible predictors of pointing accuracy • Questions: how do you like taste of this, how often do you eat it, how attractive is the stall, how many times have you purchased from this stall?

11. Farmers Market Study (New et al PRSL 2007) Key measure: After visiting all 6 stalls, participants were taken to a pointing device in the center of the market area. They could not see stalls from that area. Board was marked in 1-degree increments. Subject asked to aim the pointer at each of the 6 food items. Subject also asked to self-assess his/her general ‘sense of direction’ on a 1-7 scale. Market: 10 rows of approximately 90 stalls.

12. Hypothesis 1: Are women more accurate than men at pointing at newly learned food locations? Yes. On average 9° more accurate (27% better than men). Female advantage not due to women having more experience at FM than men. On self-assessment of ‘sense of direction’ men > women Self-assessment predicted accuracy within each sex.

13. H2: Do people remember the locations of higher-quality foods more accurately? Yes!

14. Conclusions These two studies both show differences between the sexes with respect to different spatial abilities. Strong points: Cross-cultural testing in Silverman et al, natural (field) experiment in New et al. Weak points: Neither one removes the effects of differential experience. These differences might arise naturally to the extent that males and females tend to pursue different activities during childhood. In that case we wouldn’t need to postulate specific dedicated neural modules. Perhaps these same tests should be done on young boys and girls…