[Show abstract][Hide abstract] ABSTRACT: Niche construction refers to the activities of organisms that bring about changes in their environments, many of which are evolutionarily and ecologically consequential. Advocates of niche construction theory (NCT) believe that standard evolutionary theory fails to recognize the full importance of niche construction, and consequently propose a novel view of evolution, in which niche construction and its legacy over time (ecological inheritance) are described as evolutionary processes, equivalent in importance to natural selection. Here, we subject NCT to critical evaluation, in the form of a collaboration between one prominent advocate of NCT, and a team of skeptics. We discuss whether niche construction is an evolutionary process, whether NCT obscures or clarifies how natural selection leads to organismal adaptation, and whether niche construction and natural selection are of equivalent explanatory importance. We also consider whether the literature that promotes NCT overstates the significance of niche construction, whether it is internally coherent, and whether it accurately portrays standard evolutionary theory. Our disagreements reflect a wider dispute within evolutionary theory over whether the neo-Darwinian synthesis is in need of reformulation, as well as different usages of some key terms (e.g. evolutionary process). This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Across sub-Saharan Africa, women and children play major roles as pedestrian load-transporters, in the widespread absence of basic sanitation services, electricity and affordable/reliable motorised transport. The majority of loads, including water and firewood for domestic purposes, are carried on the head. Load-carrying has implications not only for school attendance and performance, women's time budgets and gender relations, but arguably also for health and well-being. We report findings from a comprehensive review of relevant literature, undertaken June-September 2012, focussing particularly on biomechanics, maternal health, and the psycho-social impacts of load-carrying; we also draw from our own research. Key knowledge gaps and areas for future research are highlighted.
[Show abstract][Hide abstract] ABSTRACT: Summary Short sleep duration is associated with obesity in young children. This study develops the hypothesis that parental rules play a role in this association. Participants were 3-year-old children and their parents, recruited at nursery schools in socioeconomically deprived and non-deprived areas of a North-East England town. Parents were interviewed to assess their use of sleep, television-viewing and dietary rules, and given diaries to document their child's sleep for 4 days/5 nights. Children were measured for height, weight, waist circumference and triceps and subscapular skinfold thicknesses. One-hundred and eight families participated (84 with complete sleep data and 96 with complete body composition data). Parental rules were significantly associated together, were associated with longer night-time sleep and were more prevalent in the non-deprived-area compared with the deprived-area group. Television-viewing and dietary rules were associated with leaner body composition. Parental rules may in part confound the association between night-time sleep duration and obesity in young children, as rules cluster together across behavioural domains and are associated with both sleep duration and body composition. This hypothesis should be tested rigorously in large representative samples.
[Show abstract][Hide abstract] ABSTRACT: One of the most pervasive assumptions about human brain evolution is that it involved relative enlargement of the frontal lobes. We show that this assumption is without foundation. Analysis of five independent data sets using correctly scaled measures and phylogenetic methods reveals that the size of human frontal lobes, and of specific frontal regions, is as expected relative to the size of other brain structures. Recent claims for relative enlargement of human frontal white matter volume, and for relative enlargement shared by all great apes, seem to be mistaken. Furthermore, using a recently developed method for detecting shifts in evolutionary rates, we find that the rate of change in relative frontal cortex volume along the phylogenetic branch leading to humans was unremarkable and that other branches showed significantly faster rates of change. Although absolute and proportional frontal region size increased rapidly in humans, this change was tightly correlated with corresponding size increases in other areas and whole brain size, and with decreases in frontal neuron densities. The search for the neural basis of human cognitive uniqueness should therefore focus less on the frontal lobes in isolation and more on distributed neural networks.
Proceedings of the National Academy of Sciences 05/2013;
[Show abstract][Hide abstract] ABSTRACT: Health interventions increasingly rely on formative qualitative research and social marketing techniques to effect behavioural change. Few studies, however, incorporate qualitative research into the process of program evaluation to understand both impact and reach: namely, to what extent behaviour change interventions work, for whom, in what contexts, and why. We reflect on the success of a community-based hygiene intervention conducted in the slums of Kathmandu, Nepal, evaluating both maternal behaviour and infant health. We recruited all available mother-infant pairs (n = 88), and allocated them to control and intervention groups. Formative qualitative research on hand-washing practices included structured observations of 75 mothers, 3 focus groups, and 26 in-depth interviews. Our intervention was led by Community Motivators, intensively promoting hand-washing-with-soap at key junctures of food and faeces contamination. The 6-month evaluation period included hand-washing and morbidity rates, participant observation, systematic records of fortnightly community meetings, and follow-up interviews with 12 mothers. While quantitative measures demonstrated improvement in hand-washing rates and a 40% reduction in child diarrhoea, the qualitative data highlighted important equity issues in reaching the ultra-poor. We argue that a social marketing approach is inherently limited: focussing on individual agency, rather than structural conditions constraining behaviour, can unwittingly exacerbate health inequity. This contributes to a prevention paradox whereby those with the greatest need of a health intervention are least likely to benefit, finding hand-washing in the slums to be irrelevant or futile. Thus social marketing is best deployed within a range of interventions that address the structural as well as the behavioural and cognitive drivers of behaviour change. We conclude that critiques of social marketing have not paid sufficient attention to issues of health equity, and demonstrate how this can be addressed with qualitative data, embedded in both the formative and evaluative phases of a health intervention.
[Show abstract][Hide abstract] ABSTRACT: In a combinatorial communication system, some signals consist of the combinations of other signals. Such systems are more efficient than equivalent, non-combinatorial systems, yet despite this they are rare in nature. Why? Previous explanations have focused on the adaptive limits of combinatorial communication, or on its purported cognitive difficulties, but neither of these explains the full distribution of combinatorial communication in the natural world. Here, we present a nonlinear dynamical model of the emergence of combinatorial communication that, unlike previous models, considers how initially non-communicative behaviour evolves to take on a communicative function. We derive three basic principles about the emergence of combinatorial communication. We hence show that the interdependence of signals and responses places significant constraints on the historical pathways by which combinatorial signals might emerge, to the extent that anything other than the most simple form of combinatorial communication is extremely unlikely. We also argue that these constraints can be bypassed if individuals have the socio-cognitive capacity to engage in ostensive communication. Humans, but probably no other species, have this ability. This may explain why language, which is massively combinatorial, is such an extreme exception to nature's general trend for non-combinatorial communication.
Journal of The Royal Society Interface 01/2013; 10(88):20130520.
[Show abstract][Hide abstract] ABSTRACT: This research article on youth smoking in disadvantaged communities is the product of a qualitative study to understand the issues faced by young smokers - and those trying not to be smokers - in such communities. Environmental factors and peer influence are widely recognised influences on adolescents' take-up and continuation of smoking but less is known about whether, what, how and why circumstances in disadvantaged communities affect young people's pathways towards and away from smoking. Focusing on a youth club in a disadvantaged neighbourhood in the North East of England, narratives about young people's relationships with tobacco provide an ethnographically rich, thick description of the experiences of a group that is too often easily ignored. We argue that young people are caught between competing domains that together exert a form of structural violence. These are, first, the economic and political structures that have overseen de-industrialisation; second, the media structures that create desire for what they cannot afford; third the structures of international organised crime that conspire to provide them with the means to consume from which 'legitimate' structures effectively exclude them. Rather than expecting young people to comply with the health imperative, interventions need to bridge issues of agency and critical consciousness, which structural violence otherwise insidiously erodes.
Sociology of Health & Illness 11/2012;
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