arXiv subjects

Lewis G. Halsey

Publications and source records attributed to Lewis G. Halsey.

3 recordsLinked to original sources

arXiv2026

The vulnerable male brain: Men's spatial abilities are condition-dependent, sexually selected traits

Traits that are exaggerated in one sex relative to the other sex might be more vulnerable to stressor exposure because the development and expression of these traits are costly. Sex differences in such traits should therefore be smaller in populations with high stressor exposure. We tested this prediction in humans by examining the magnitude of men's advantage in spatial cognition and women's advantage in emotion recognition across nations that varied in their level of development. As predicted, men's advantage in spatial cognition was larger in nations relatively buffered from stressors. However, in contrast to our prediction, women's advantage in emotion recognition was constant across nations, suggesting aspects of men's cognition might be particularly vulnerable to early or current conditions. The samples were biased toward higher income and healthier individuals for nations in which men's spatial cognition was compromised; thus, we are likely underestimating the effects of living conditions on men's spatial cognition. The results further our understanding of how social and environmental conditions can have sex-specific effects on human cognition.

q-bio.NC↗

arXiv2025

The sexy and formidable male body: men's height and weight are condition-dependent, sexually selected traits

On average men are taller and more muscular than women, which confers on them advantages related to female choice and during physical competition with other men. Sexual size dimorphisms such as these come with vulnerabilities due to higher maintenance and developmental costs for the sex with the larger trait. These costs are in keeping with evolutionary theory that posits large, elaborate, sexually selected traits are signals of health and vitality because stressor exposure (e.g.\ early disease) will compromise them (e.g.\ shorter stature) more than other traits. We provide a large-scale test of this hypothesis for the human male and show that with cross-national and cross-generational improvements in living conditions, where environmental stressors recede, men's gains in height and weight are more than double those of women's, increasing sexual size dimorphism. Our study combines evolutionary biology with measures of human wellbeing, providing novel insights into how socio-ecological factors and sexual selection shape key physical traits.

q-bio.PE↗

arXiv2021

The mystery of energy compensation

The received wisdom on how activity affects energy expenditure is that the more activity is undertaken, the more calories will have been burned by the end of the day. Yet traditional hunter-gatherers, who lead physically hard lives, burn no more calories each day than western populations living in labour-saving environments. Indeed, there is now a wealth of data, both for humans and other animals, demonstrating that long-term lifestyle changes involving increases in exercise or other physical activities do not result in commensurate increases in daily energy expenditure (DEE). This is because humans and other animals exhibit a degree of energy compensation at the organismal level, ameliorating some of the increases in DEE that would occur from the increased activity by decreasing the energy expended on other biological processes. And energy compensation can be sizable, reaching many hundreds of calories in humans. But the processes that are downregulated in the long-term to achieve energy compensation are far from clear, particularly in humans. We do not know how energy compensation is achieved. My review here of the literature on relevant exercise intervention studies, for both humans and other species, indicates conflict regarding the role that basal metabolic rate (BMR) or low level activity such as fidgeting play, if any, particularly once changes in body composition are factored out. In situations where BMR and low-level activity are not major components of energy compensation, what then drives it? I discuss how changes in mitochondrial efficiency and changes in circadian fluctuations in BMR may contribute to our understanding of energy management. Currently unexplored, these mechanisms and others may provide important insights into the mystery of how energy compensation is achieved.

q-bio.OT↗