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1.
Evol Hum Sci ; 6: e11, 2024.
Article En | MEDLINE | ID: mdl-38516373

Among vertebrates, allomothering (non-maternal care) is classified as cooperative breeding (help from sexually mature non-breeders, usually close relatives) or communal breeding (shared care between multiple breeders who are not necessarily related). Humans have been described with both labels, most frequently as cooperative breeders. However, few studies have quantified the relative contributions of allomothers according to whether they are (a) sexually mature and reproductively active and (b) related or unrelated. We constructed close-proximity networks of Agta and BaYaka hunter-gatherers. We used portable remote-sensing devices to quantify the proportion of time children under the age of 4 spent in close proximity to different categories of potential allomother. Both related and unrelated, and reproductively active and inactive, campmates had substantial involvement in children's close-proximity networks. Unrelated campmates, siblings and subadults were the most involved in both populations, whereas the involvement of fathers and grandmothers was the most variable between the two populations. Finally, the involvement of sexually mature, reproductively inactive adults was low. Where possible, we compared our findings with studies of other hunter-gatherer societies, and observed numerous consistent trends. Based on our results we discuss why hunter-gatherer allomothering cannot be fully characterised as cooperative or communal breeding.

2.
Proc Natl Acad Sci U S A ; 121(9): e2318181121, 2024 Feb 27.
Article En | MEDLINE | ID: mdl-38346210

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities-incorporating market integration-are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as "farmers" did not have higher fertility than others, while "foragers" did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence.


Economics , Fertility , Female , Humans , Population Dynamics , Socioeconomic Factors , Developing Countries
3.
Dev Psychol ; 60(3): 422-440, 2024 Mar.
Article En | MEDLINE | ID: mdl-37956035

Attachment theory postulates that there is a particular style of caregiving that, because of its interaction with our evolved psychology, is most likely to result in healthy psychological development. Attachment research has been criticized because most studies have been conducted with Western populations. Critics argue this has (a) overemphasized the importance of sensitive responsive caregiving and (b) limited our understanding of multiple nonmaternal caregiving (allomothering). Here, we analyze the extent of sensitive responsiveness and structural properties of allomothering networks among Mbendjele hunter-gatherers who reside in the Republic of Congo. Humans lived as hunter-gatherers for the majority of our evolutionary history, thus studying contemporary hunter-gatherers can offer insight into the caregiving children may be psychologically adapted to. Based on 12-hr focal follows of 18 children (0-4 years old; 10 male), we constructed caregiving networks across the domains of responding to crying, physical contact, interactive care, and proximity. Crying was virtually always responded to rapidly via comforting and never via scolding. Children received physical contact and care for the majority of the day. Allomothering accounted for 40%-50% of caregiving in each domain. While allomaternal networks were large, they were highly concentrated-the majority of a child's allocare was provided by just a few caregivers. Due to high caregiver:child ratios, "sharing" of caregivers was limited-a child typically had several allomothers who directed a majority of their allomaternal effort to him/her. These findings add to our understanding of the level and sources of sensitive responsive caregiving that children may be evolutionarily primed to expect. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Caregivers , Crying , Female , Child , Humans , Male , Infant, Newborn , Infant , Child, Preschool , Caregivers/psychology
4.
Cureus ; 15(11): e49328, 2023 Nov.
Article En | MEDLINE | ID: mdl-38143681

Background Reusable phlebotomy tourniquets may become contaminated through repeated use on the skin surfaces of multiple patients, the hands of healthcare workers, or various surfaces. Noncompliance with the protocol guidelines for managing tourniquets can contribute to the cross-transmission of microorganisms among patients. This study was conducted to determine the microbial flora and antimicrobial sensitivity pattern of reusable phlebotomy tourniquets. Methodology Tourniquets were randomly sampled across the different areas of the hospital and were transported to the microbiology laboratory for isolation, identification, and antibiotic susceptibility testing of microorganisms using standard microbiological techniques. Results The overall bacterial colonization rate of the 50 tourniquets was 80%. The most prevalent isolate on tourniquets was Coagulase-negative Staphylococcus (9, 22.54%), followed by Micrococcus (6, 15%), Staphylococcus aureus (5, 12.5%), diphtheroid (5, 12.5%), Acinetobacter (4, 10%) Enterococcus (3, 7.5%), Pseudomonas (3, 7.5%), Bacillus (3, 7.5%), and Escherichia coli (2, 5%). Conclusions Regular surveillance and disinfection of reusable tourniquets in resource-poor settings are recommended to decrease healthcare infections and the transmission of multidrug-resistant (MDR) strains.

5.
Cureus ; 15(8): e42801, 2023 Aug.
Article En | MEDLINE | ID: mdl-37674939

Introduction Outcome-Based Education (OBE) is an education model for students that assist the teachers to outline the cause and evaluation with goals in mind to achieve results such as Program Outcome (PO) and Course Outcome (CO) which forms the basis for evaluating student performance. Materials and methods This study was conducted with the participants to discuss the hardships faced while implementing Competency-Based Medical Education (CBME). Need-gap analysis based on CBME guidelines was performed. Detailed discussion was done with department faculty to plan. Results Internal and final evaluations were done for all the students. When compared with conventional didactic lectures remarkable improvement in academic results of the students were noted which were statistically significant with p value less than 0.001. Conclusion CBME is not just adding capabilities but also achieving and strengthening these capabilities with a proper educational approach and efficacious evaluation methods.

6.
Evol Hum Sci ; 5: e9, 2023.
Article En | MEDLINE | ID: mdl-37587930

Here we investigate the effects of extensive sociality and mobility on the oral microbiome of 138 Agta hunter-gatherers from the Philippines. Our comparisons of microbiome composition showed that the Agta are more similar to Central African BaYaka hunter-gatherers than to neighbouring farmers. We also defined the Agta social microbiome as a set of 137 oral bacteria (only 7% of 1980 amplicon sequence variants) significantly influenced by social contact (quantified through wireless sensors of short-range interactions). We show that large interaction networks including strong links between close kin, spouses and even unrelated friends can significantly predict bacterial transmission networks across Agta camps. Finally, we show that more central individuals to social networks are also bacterial supersharers. We conclude that hunter-gatherer social microbiomes are predominantly pathogenic and were shaped by evolutionary tradeoffs between extensive sociality and disease spread.

7.
Cureus ; 15(7): e42434, 2023 Jul.
Article En | MEDLINE | ID: mdl-37637615

Introduction Blood tests are essential for detecting and treating hospitalized individuals with diseases. Laboratory blood tests provide doctors with critical information required to treat their patient's illnesses. The most common sources of error in clinical laboratories are pre-analytical errors. Although quality control measures can remediate analytical errors, there is a requirement for stringent quality checks in the pre-analytical sector as these activities are performed outside of the laboratory. Pre-analytical errors when combined with the sigma value can reflect a better picture as the sigma value represents the laboratory's performance.  Aim In this study, six sigma and the Pareto principle were utilized to assess pre-analytical quality indicators for evaluating the performance of a clinical hematology laboratory.  Methodology  This is a retrospective observational study conducted from 2015 to 2023 (for a period of eight years). Information about the frequency of pre-analytical errors was retrieved from the hematology section of the central diagnostic research laboratory information system and the data was entered into an MS Excel sheet and data was evaluated utilizing SPSS version 23 (IBM Corp., Armonk, NY). Results In the current research, total of 15 pre-analytical errors were noted. Out of the total 15 pre-analytical errors studied, 55.4% of pre-analytical errors were noted among which 80% errors were due to lack of mention of sample type or received time and 20% of errors were attributed to no mention of diagnosis in requisition forms. The next most common errors noted were insufficient samples (8.26%) followed by absence of physician's signature (7%), incomplete request form (5.4%), age (4.2%), unique hospital identification (UHID) number (3.7%), clotted samples and transportation of the samples (3.6%), date and incorrect vials (2.6%). Gender (0.95%), hemolysed (0.85%), and lipemic samples (0.45%). Hemolysed and lipemic samples had a sigma value of 4.4 and 4.6, respectively, whereas gender and age had a sigma value of 4.3 and 3.8, inadequate sample for testing and an incorrect anticoagulant to blood ratio had a sigma value of 3.6, indicating that sample collection has to be improved as the inverse relationship is noted between sigma value and laboratory performance. Conclusion Pareto chart and sigma value can help recognize most common pre-analytical errors, which consequently will help to prevent further recurrence of pre-analytical errors. Adequate training with regard to best practices in phlebotomy for interns, clinicians and technicians must be provided to decrease quantitative errors, which will further enhance total quality management in the laboratory.

8.
PLoS One ; 18(4): e0284360, 2023.
Article En | MEDLINE | ID: mdl-37099506

Examining development is essential for a full understanding of behaviour, including how individuals acquire traits and how adaptive evolutionary forces shape these processes. The present study explores the development of cooperative behaviour among the Agta, a Filipino hunter-gatherer population. A simple resource allocation game assessing both levels of cooperation (how much children shared) and patterns of partner choice (who they shared with) was played with 179 children between the ages of 3 and 18. Children were given five resources (candies) and for each was asked whether to keep it for themselves or share with someone else, and if so, who this was. Between-camp variation in children's cooperative behaviour was substantial, and the only strong predictor of children's cooperation was the average level of cooperation among adults in camp; that is, children were more cooperative in camps where adults were more cooperative. Neither age, sex, relatedness or parental levels of cooperation were strongly associated with the amount children shared. Children preferentially shared with close kin (especially siblings), although older children increasingly shared with less-related individuals. Findings are discussed in terms of their implications for understanding cross-cultural patterns of children's cooperation, and broader links with human cooperative childcare and life history evolution.


Camping , Cooperative Behavior , Adolescent , Adult , Child , Child, Preschool , Humans , Asian People , Child Health , Siblings
9.
J Child Psychol Psychiatry ; 64(10): 1522-1525, 2023 10.
Article En | MEDLINE | ID: mdl-36882094

Humans lived as hunter-gatherers for more than 95% of our evolutionary history, thus studying contemporary hunter-gatherer populations offers insight into the conditions children may be psychologically adapted to. Here, we contrast hunter-gatherer childhoods with those of WEIRD (Western Educated Industrialised Rich Democratic) societies and consider the implications for children's mental health. Hunter-gatherer infants receive continuous physical contact and more sensitive and responsive caregiving than is typical of WEIRD societies, due to the extensive involvement of alloparents (non-parental caregivers) who generally provide 40-50% of their care. Alongside positive attachment outcomes, alloparenting likely reduces the harms of family adversity and risk of abuse/neglect. From late infancy, hunter-gatherers spend their time in mixed-age 'playgroups' where they learn via active play and exploration without adult supervision. This contrasts with WEIRD norms surrounding the need for adult supervision of children, as well as with the passive teacher-led classrooms, which could potentially lead to suboptimal learning outcomes and pose difficulties to children with ADHD. Based on this preliminary comparison, we consider practical solutions to potential harms arising from discordance between what children are adapted to and exposed to. These include infant massage and babywearing; increased sibling and extra-familial involvement in childcare; and educational adjustments.


Child Care , Mental Health , Adult , Humans , Child
10.
PLoS One ; 16(10): e0258384, 2021.
Article En | MEDLINE | ID: mdl-34705859

Ethnographers frequently allude to alcoholism and related harms in Indigenous hunter-gatherer communities, but very few studies have quantified patterns of alcohol consumption or its health and social impacts. We present a case study of the Mbendjele BaYaka, a Congolese population undergoing socioeconomic transition. 83 adults answered questions about their frequency and quantity of alcohol consumption, underwent biometric measurements and reported whether they were currently experiencing a cough or diarrhoea; 56 participated in structured interviews about their experiences with alcohol. Based on WHO standards, we found 44.3% of the full sample, and 51.5% of drinkers (excluding abstainers), had a hazardous volume of alcohol consumption; and 35.1% of the full sample, and 40.9% of drinkers, engaged in heavy episodic drinking; consumption habits varied with sex and age. Total weekly consumption was a positive predictor of blood pressure and the likelihood of experiencing diarrhoea; associations with other biometric variables were not statistically significant. Interview responses indicated numerous other economic, mental and physical health harms of alcohol use, the prevalence of which demonstrate some variability between forest camps and permanent village settlements. These include high rates of drinking during pregnancy and breastfeeding (~40%); frequent alcohol-induced violence; and considerable exchange of foraged foods and engagement in exploitative labour activities to acquire alcohol or repay associated debts. Our findings demonstrate the prevalence of hazardous alcohol consumption among transitioning hunter-gatherers is higher than other segments of the Congolese population and indicate negative impacts on health and wellbeing, highlighting an urgent need for targeted public health interventions.


Alcoholism , Cross-Sectional Studies , Humans , Male , Middle Aged , Prevalence , Risk Factors
11.
Glob Cardiol Sci Pract ; 2021(2): e202113, 2021 Jun 30.
Article En | MEDLINE | ID: mdl-34285904

Background: Heart failure is a leading killer worldwide, with concurrent anaemia and iron deficiency portending sepulchral prognosis. Anaemia is rampant, with 53% prevalence in Indian females, but iron deficiency can be present even without anaemia. Therefore, this study was planned to determine the clinical profile, red blood cell indices, and effects of iron deficiency, on the course and prognosis of heart failure in Indian females. Materials and methods: This was a hospital-based observational study, conducted at a tertiary care teaching institute in India. Data from 147 females enrolled in the study between September 2017 to March 2020 was collected out of all patients enrolled in ongoing heart failure registry at the institute. Clinical characteristics at presentation, iron profile, red blood cell indices, treatment and mortality data was collected. Results: Mean age of the subjects (n = 147) was 53.31 ± 17.1 years with 55% non-rheumatic and 45% with rheumatic heart disease. The patients with rheumatic heart disease were younger, with a higher prevalence of atrial fibrillation. Non-rheumatic patients had a higher prevalence of CV risk factors like diabetes, hypertension, renal failure, more patients in NYHA IV, and 83% patients had LVEF ≤40%. Anaemia was present in 49%, however iron deficiency was present in 89% (absolute iron deficiency in 80% and functional iron deficiency in 9%) with no significant difference between rheumatic and non-rheumatic group. Red blood cell indices showed no significant difference across the spectrum of iron deficiency and anaemia, except lower mean corpuscular volume in patients with both iron deficiency and anaemia. The mean survival time was 840 days, with no significant difference between groups. There was significantly higher mortality in patients with iron deficiency (log rank 0.045). Conclusion: Iron deficiency-with or without anaemia-is very high in Indian females, worsening survival in heart failure. Proper diagnosis with iron supplementation will improve the prognosis.

12.
Philos Trans R Soc Lond B Biol Sci ; 376(1827): 20200026, 2021 06 21.
Article En | MEDLINE | ID: mdl-33938270

Non-maternal carers (allomothers) are hypothesized to lighten the mother's workload, allowing for the specialized human life history including relatively short interbirth intervals and multiple dependent offspring. Here, using in-depth observational data on childcare provided to 78 Agta children (a foraging population in the northern Philippines; aged 0-6 years), we explore whether allomaternal childcare substitutes and decreases maternal childcare. We found that allomother caregiving was associated with reduced maternal childcare, but the substitutive effect varied depending on the source and type of care. Children-only playgroups consistently predicted a decrease in maternal childcare. While grandmothers were rarely available, their presence was negatively associated with maternal presence and childcare, and grandmothers performed similar childcare activities to mothers. These results underscore the importance of allomothering in reducing maternal childcare in the Agta. Our findings suggest that flexibility in childcare sources, including children-only playgroups, may have been the key to human life-history evolution. Overall, our results reinforce the necessity of a broad conceptualization of social support in human childcare. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'.


Child Care , Cooperative Behavior , Mothers , Parenting , Social Support , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Mothers/psychology , Mothers/statistics & numerical data , Philippines , Play and Playthings
13.
Evol Hum Sci ; 2: e24, 2020.
Article En | MEDLINE | ID: mdl-37588372

Cultures around the world are converging as populations become more connected. On the one hand this increased connectedness can promote the recombination of existing cultural practices to generate new ones, but on the other it may lead to the replacement of traditional practices and global WEIRDing. Here we examine the process and causes of changes in cultural traits concerning wild plant knowledge in Mbendjele BaYaka hunter-gatherers from Congo. Our results show that the BaYaka who were born in town reported knowing and using fewer plants than the BaYaka who were born in forest camps. Plant uses lost in the town-born BaYaka related to medicine. Unlike the forest-born participants, the town-born BaYaka preferred Western medicine over traditional practices, suggesting that the observed decline of plant knowledge and use is the result of replacement of cultural practices with the new products of cumulative culture.

14.
Nat Hum Behav ; 3(11): 1154-1163, 2019 11.
Article En | MEDLINE | ID: mdl-31406338

Human children are frequently cared for by non-parental caregivers (alloparents), yet few studies have conducted systematic alternative hypothesis tests of why alloparents help. Here we explore whether predictions from kin selection, reciprocity, learning-to-mother and costly signalling hypotheses explain non-parental childcare among Agta hunter-gatherers from the Philippines. To test these hypotheses, we used high-resolution proximity data from 1,701 child-alloparent dyads. Our results indicated that reciprocity and relatedness were positively associated with the number of interactions with a child (our proxy for childcare). Need appeared more influential in close kin, suggesting indirect benefits, while reciprocity proved to be a stronger influence in non-kin, pointing to direct benefits. However, despite shared genes, close and distant kin interactions were also contingent on reciprocity. Compared with other apes, humans are unique in rapidly producing energetically demanding offspring. Our results suggest that the support that mothers require is met through support based on kinship and reciprocity.


Caregivers , Child Care , Parenting , Parents , Adolescent , Adult , Aged , Anthropology, Cultural , Child , Child, Preschool , Cooperative Behavior , Family , Female , Humans , Infant , Male , Middle Aged , Philippines , Social Behavior , Young Adult
15.
Sci Rep ; 9(1): 11080, 2019 07 31.
Article En | MEDLINE | ID: mdl-31367002

High-fidelity transmission of information through imitation and teaching has been proposed as necessary for cumulative cultural evolution. Yet, it is unclear when and for which knowledge domains children employ different social learning processes. This paper explores the development of social learning processes and play in BaYaka hunter-gatherer children by analysing video recordings and time budgets of children from early infancy to adolescence. From infancy to early childhood, hunter-gatherer children learn mainly by imitating and observing others' activities. From early childhood, learning occurs mainly in playgroups and through practice. Throughout childhood boys engage in play more often than girls whereas girls start foraging wild plants from early childhood and spend more time in domestic activities and childcare. Sex differences in play reflect the emergence of sexual division of labour and the play-work transition occurring earlier for girls. Consistent with theoretical models, teaching occurs for skills/knowledge that cannot be transmitted with high fidelity through other social learning processes such as the acquisition of abstract information e.g. social norms. Whereas, observational and imitative learning occur for the transmission of visually transparent skills such as tool use, foraging, and cooking. These results suggest that coevolutionary relationships between human sociality, language and teaching have likely been fundamental in the emergence of human cumulative culture.


Learning/physiology , Social Learning/physiology , Child , Congo , Cooperative Behavior , Cultural Evolution , Female , Humans , Knowledge , Male , Sex Characteristics , Social Behavior
16.
Nat Commun ; 8(1): 1853, 2017 12 05.
Article En | MEDLINE | ID: mdl-29208949

Storytelling is a human universal. From gathering around the camp-fire telling tales of ancestors to watching the latest television box-set, humans are inveterate producers and consumers of stories. Despite its ubiquity, little attention has been given to understanding the function and evolution of storytelling. Here we explore the impact of storytelling on hunter-gatherer cooperative behaviour and the individual-level fitness benefits to being a skilled storyteller. Stories told by the Agta, a Filipino hunter-gatherer population, convey messages relevant to coordinating behaviour in a foraging ecology, such as cooperation, sex equality and egalitarianism. These themes are present in narratives from other foraging societies. We also show that the presence of good storytellers is associated with increased cooperation. In return, skilled storytellers are preferred social partners and have greater reproductive success, providing a pathway by which group-beneficial behaviours, such as storytelling, can evolve via individual-level selection. We conclude that one of the adaptive functions of storytelling among hunter gatherers may be to organise cooperation.


Biological Evolution , Cooperative Behavior , Narration , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Philippines/ethnology , Young Adult
17.
PeerJ ; 5: e3497, 2017.
Article En | MEDLINE | ID: mdl-28875065

BACKGROUND: In light of the rapid decrease in fossils fuel reserves and an increasing demand for energy, novel methods are required to explore alternative biofuel production processes to alleviate these pressures. A wide variety of molecules which can either be used as biofuels or as biofuel precursors are produced using microbial enzymes. However, the common challenges in the industrial implementation of enzyme catalysis for biofuel production are the unavailability of a comprehensive biofuel enzyme resource, low efficiency of known enzymes, and limited availability of enzymes which can function under extreme conditions in the industrial processes. METHODS: We have developed a comprehensive database of known enzymes with proven or potential applications in biofuel production through text mining of PubMed abstracts and other publicly available information. A total of 131 enzymes with a role in biofuel production were identified and classified into six enzyme classes and four broad application categories namely 'Alcohol production', 'Biodiesel production', 'Fuel Cell' and 'Alternate biofuels'. A prediction tool 'Benz' was developed to identify and classify novel homologues of the known biofuel enzyme sequences from sequenced genomes and metagenomes. 'Benz' employs a hybrid approach incorporating HMMER 3.0 and RAPSearch2 programs to provide high accuracy and high speed for prediction. RESULTS: Using the Benz tool, 153,754 novel homologues of biofuel enzymes were identified from 23 diverse metagenomic sources. The comprehensive data of curated biofuel enzymes, their novel homologs identified from diverse metagenomes, and the hybrid prediction tool Benz are presented as a web server which can be used for the prediction of biofuel enzymes from genomic and metagenomic datasets. The database and the Benz tool is publicly available at http://metabiosys.iiserb.ac.in/biofueldb& http://metagenomics.iiserb.ac.in/biofueldb.

18.
Sci Rep ; 7(1): 9751, 2017 08 29.
Article En | MEDLINE | ID: mdl-28852076

The human gut microbiota is constituted of a diverse group of microbial species harbouring an enormous metabolic potential, which can alter the metabolism of orally administered drugs leading to individual/population-specific differences in drug responses. Considering the large heterogeneous pool of human gut bacteria and their metabolic enzymes, investigation of species-specific contribution to xenobiotic/drug metabolism by experimental studies is a challenging task. Therefore, we have developed a novel computational approach to predict the metabolic enzymes and gut bacterial species, which can potentially carry out the biotransformation of a xenobiotic/drug molecule. A substrate database was constructed for metabolic enzymes from 491 available human gut bacteria. The structural properties (fingerprints) from these substrates were extracted and used for the development of random forest models, which displayed average accuracies of up to 98.61% and 93.25% on cross-validation and blind set, respectively. After the prediction of EC subclass, the specific metabolic enzyme (EC) is identified using a molecular similarity search. The performance was further evaluated on an independent set of FDA-approved drugs and other clinically important molecules. To our knowledge, this is the only available approach implemented as 'DrugBug' tool for the prediction of xenobiotic/drug metabolism by metabolic enzymes of human gut microbiota.


Bacteria/enzymology , Bacteria/metabolism , Enzymes/genetics , Enzymes/metabolism , Gastrointestinal Microbiome , Microbiota , Xenobiotics/metabolism , Bacteria/classification , Bacteria/genetics , Biotransformation , Computational Biology/methods , Humans , Metabolic Networks and Pathways/genetics
19.
Proc Natl Acad Sci U S A ; 114(31): 8205-8210, 2017 08 01.
Article En | MEDLINE | ID: mdl-28696282

Precise estimation of age is essential in evolutionary anthropology, especially to infer population age structures and understand the evolution of human life history diversity. However, in small-scale societies, such as hunter-gatherer populations, time is often not referred to in calendar years, and accurate age estimation remains a challenge. We address this issue by proposing a Bayesian approach that accounts for age uncertainty inherent to fieldwork data. We developed a Gibbs sampling Markov chain Monte Carlo algorithm that produces posterior distributions of ages for each individual, based on a ranking order of individuals from youngest to oldest and age ranges for each individual. We first validate our method on 65 Agta foragers from the Philippines with known ages, and show that our method generates age estimations that are superior to previously published regression-based approaches. We then use data on 587 Agta collected during recent fieldwork to demonstrate how multiple partial age ranks coming from multiple camps of hunter-gatherers can be integrated. Finally, we exemplify how the distributions generated by our method can be used to estimate important demographic parameters in small-scale societies: here, age-specific fertility patterns. Our flexible Bayesian approach will be especially useful to improve cross-cultural life history datasets for small-scale societies for which reliable age records are difficult to acquire.


Aging , Anthropology/methods , Adolescent , Adult , Age Distribution , Aged , Aged, 80 and over , Bayes Theorem , Female , Fertility , Humans , Markov Chains , Middle Aged , Philippines , Population Density , Reproducibility of Results , Societies , Uncertainty
20.
Sci Rep ; 7(1): 1153, 2017 04 25.
Article En | MEDLINE | ID: mdl-28442785

Individuals' centrality in their social network (who they and their social ties are connected to) has been associated with fertility, longevity, disease and information transmission in a range of taxa. Here, we present the first exploration in humans of the relationship between reproductive success and different measures of network centrality of 39 Agta and 38 BaYaka mothers. We collected three-meter contact ('proximity') networks and reproductive histories to test the prediction that individual centrality is positively associated with reproductive fitness (number of living offspring). Rather than direct social ties influencing reproductive success, mothers with greater indirect centrality (i.e. centrality determined by second and third degree ties) produced significantly more living offspring. However, indirect centrality is also correlated with sickness in the Agta, suggesting a trade-off. In complex social species, the optimisation of individuals' network position has important ramifications for fitness, potentially due to easy access to different parts of the network, facilitating cooperation and social influence in unpredictable ecologies.


Reproductive Behavior , Social Support , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Longevity , Middle Aged , Models, Biological , Young Adult
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