Fetal load and the evolution of lumbar lordosis in bipedal hominins

Whitcome, Katherine K.; Shapiro, Liza J.; Lieberman, Daniel E.

doi:10.1038/nature06342

Cited by 233 publications

(271 citation statements)

References 33 publications

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“…The muscular fatigue and lower back pain resulting from this hip torque would have impaired foraging efficiency (Whitcome et al, 2007). This would have left women and their families-including fetus, offspring, and mate-at risk of nutritional stress (Marlowe, 2003;Whitcome et al, 2007). Selection would therefore have favored morphological adaptation in women that enabled them to shift the gravid COM back over the hips.…”

Section: Pregnancy and Lumbar Curvaturementioning

confidence: 99%

“…This wedging helps pregnant women shift their COM back over their hips, thereby reducing hip torque by over 90% (Whitcome et al, 2007). The inability to shift the COM back over Evolution and Human Behavior 36 (2015) 345-350 the hip joints, on the other hand, results in sustained contraction of the lower back muscles, which increases risk of fatigue and injury (White & Punjabi, 1990).…”

Section: Pregnancy and Lumbar Curvaturementioning

confidence: 99%

“…If this COM were not moved back over the hips, ancestral women would have been subjected to a nearly 800% increase in hip torque during pregnancy (Whitcome, Shapiro, & Lieberman, 2007). The muscular fatigue and lower back pain resulting from this hip torque would have impaired foraging efficiency (Whitcome et al, 2007).…”

Section: Pregnancy and Lumbar Curvaturementioning

confidence: 99%

“…The female hominin spine 1 -but not the male hominin spinepossesses evolved morphology to deal with this adaptive challenge: women possess wedging in the third-to-last lumbar vertebra (Whitcome et al, 2007). This wedging helps pregnant women shift their COM back over their hips, thereby reducing hip torque by over 90% (Whitcome et al, 2007).…”

Section: Pregnancy and Lumbar Curvaturementioning

confidence: 99%

“…These countervailing forces would have resulted in stabilizing selection on ancestral women's spines. Selection would have favored vertebrae in women that were (1) sufficiently wedged to center the gravid COM back over the hips, but nonetheless (2) provided sufficient skeletal reinforcement to prevent hyperlordosis, fatigue, and spinal injury (White & Punjabi, 1990;Whitcome et al, 2007).…”

Section: Pregnancy and Lumbar Curvaturementioning

confidence: 99%

See 4 more Smart Citations

Lumbar curvature: a previously undiscovered standard of attractiveness

Lewis

Russell

Al-Shawaf

et al. 2015

Evolution and Human Behavior

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This paper reports independent studies supporting the proposal that human standards of attractiveness reflect the output of psychological adaptations to detect fitness-relevant traits. We tested novel a priori hypotheses based on an adaptive problem uniquely faced by ancestral hominin females: a forward-shifted center of mass during pregnancy. The hominin female spine possesses evolved morphology to deal with this adaptive challenge: wedging in the third-to-last lumbar vertebra. Among ancestral women, vertebral wedging would have minimized the net fitness threats posed by hypolordosis and hyperlordosis, thereby creating selective pressures on men to prefer such women as mates. On this basis, we hypothesized that men possess evolved mate preferences for women with this theoretically optimal angle of lumbar curvature. In Study 1, as hypothesized, men's attraction toward women increased as women's lumbar curvature approached this angle. However, vertebral wedging and buttock mass can both influence lumbar curvature. Study 2 thus employed a forced-choice paradigm in which men selected the most attractive woman among models exhibiting the same lumbar curvature, but for different morphological reasons. Men again tended to prefer women exhibiting cues to a degree of vertebral wedging closer to optimum. This included preferring women whose lumbar curvature specifically reflected vertebral wedging rather than buttock mass. These findings reveal novel, theoretically anchored, and previously undiscovered standards of attractiveness.

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Section: Pregnancy and Lumbar Curvaturementioning

confidence: 99%

Section: Pregnancy and Lumbar Curvaturementioning

confidence: 99%