210
670.90
3.19
279

Publication History View all

  • Source
    [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.
    Evolution 12/2013;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of the study was to examine the relationship between self-reported stress levels among new mothers in São Paulo, Brazil and two biomarkers of stressful experience, oxytocin (OT) and Epstein-Barr Virus antibody level (EBV-ab), with planned pregnancy hypothesized as a moderator of biological response to stressful conditions. Sixty-three first-time mothers between the ages of 15 and 45 were recruited from neighborhoods in São Paulo, Brazil. Quantitative and qualitative data were collected longitudinally, bi-weekly between two and 12 weeks postpartum. OT level was assessed from breast milk samples and EBV-ab from blood spot samples. An Interpersonal Satisfaction scale was developed, validated, and administered, along with the Cohen perceived stress scale (PSS). In-depth interview data revealed unplanned pregnancy to be a significant stressor in the lives of first-time mothers. In linear regression, OT level was negatively associated with interpersonal satisfaction score (P = 0.022) and positively associated with PSS score (P = 0.007). When splitting the sample by planned status of the pregnancy, women with an unplanned pregnancy showed a strengthened positive association between OT level and PSS (P = 0.001; Adj R(2) = 0.44) and negative association with interpersonal satisfaction (P = 0.017; Adj R(2) = 0.15), while no associations existed for women with a planned pregnancy. EBV-ab level was not correlated or associated with stress/satisfaction measures. OT is an effective biomarker in the measurement of stress in the body, and additionally reflects differential experiences with difficult interpersonal circumstances, such as unplanned pregnancy. By contrast, EBV-ab failed to reflect differences in self-reported stress levels between mothers. Am. J. Hum. Biol., 2013. © 2013 Wiley Periodicals, Inc.
    American Journal of Human Biology 11/2013;
  • [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.
    Social Science [?] Medicine 07/2013; 88C:90-97.
  • Source
    [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.
    Journal of Biosocial Science 06/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: A large body of evidence suggests that major histocompatibility complex (MHC) genotype influences mate choice. However, few studies have investigated MHC-mediated post-copulatory mate choice under natural, or even semi-natural, conditions. We set out to explore this question in a large semi-free-ranging population of mandrills (Mandrillus sphinx) using MHC-DRB genotypes for 127 parent-offspring triads. First, we showed that offspring MHC heterozygosity correlates positively with parental MHC dissimilarity suggesting that mating among MHC dissimilar mates is efficient in increasing offspring MHC diversity. Second, we compared the haplotypes of the parental dyad with those of the offspring to test whether post-copulatory sexual selection favored offspring with two different MHC haplotypes, more diverse gamete combinations, or greater within-haplotype diversity. Limited statistical power meant that we could only detect medium or large effect sizes. Nevertheless, we found no evidence for selection for heterozygous offspring when parents share a haplotype (large effect size), genetic dissimilarity between parental haplotypes (we could detect an odds ratio of ≥1.86), or within-haplotype diversity (medium-large effect). These findings suggest that comparing parental and offspring haplotypes may be a useful approach to test for post-copulatory selection when matings cannot be observed, as is the case in many study systems. However, it will be extremely difficult to determine conclusively whether post-copulatory selection mechanisms for MHC genotype exist, particularly if the effect sizes are small, due to the difficulty in obtaining a sufficiently large sample. Am. J. Primatol. 9999:1-11, 2013. © 2013 Wiley Periodicals, Inc.
    American Journal of Primatology 05/2013;
  • Source
    [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.
    Social Science [?] Medicine 04/2013; 83:133-41.
  • Source
    [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.
  • BMJ (online) 01/2013; 346:f2344.
  • Source
    [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.
Information provided on this web page is aggregated encyclopedic and bibliographical information relating to the named institution. Information provided is not approved by the institution itself. The institution’s logo (and/or other graphical identification, such as a coat of arms) is used only to identify the institution in a nominal way. Under certain jurisdictions it may be property of the institution.