Human prosociality is one of the defining characteristics of our species, yet the ontogeny of alt... more Human prosociality is one of the defining characteristics of our species, yet the ontogeny of altruistic behavior remains poorly understood. The evolution of widespread food sharing in humans helped shape cooperation, family formation, life history, language, and the development of economies of scale. While the behavioral and ecological correlates of food sharing among adults are widely studied, very little is known about food sharing among children. Here, in the first study to analyze the food sharing patterns of hunter-gatherer children, we show that while sharing may be biased towards kin, reciprocity characterizes the majority of all sharing dyads, both related and unrelated. These data lend support to the recent claim that discrimination among kin might be linked with reciprocal altruism theory. Furthermore, we show that age positively correlates with an increase in sharing, both in frequency and amount, supporting recent suggestions that prosocial behaviors and egalitarianism develop strongly in middle childhood when children acquire the normative rules of their society.
Through human microbiome sequencing, we can
better understand how host evolutionary and ontogenet... more Through human microbiome sequencing, we can better understand how host evolutionary and ontogenetic history is reflected in the microbial function. However, there has been no information on the gut metagenome configuration in hunter-gatherer populations, posing a gap in our knowledge of gut microbiota (GM)-host mutualism arising from a lifestyle that describes over 90% of human evolutionary history. Here, we present the first metagenomic analysis of GM from Hadza hunter-gatherers of Tanzania, showing a unique enrichment in metabolic pathways that aligns with the dietary and environmental factors characteristic of their foraging lifestyle. We found that the Hadza GM is adapted for broad-spectrum carbohydrate metabolism, reflecting the complex polysaccharides in their diet. Furthermore, the Hadza GM is equipped for branched-chain amino acid degradation and aromatic amino acid biosynthesis. Resistome functionality demonstrates the existence of antibiotic resistance genes in a population with little antibiotic exposure, indicating the ubiquitous presence of environmentally derived resistances. Our results demonstrate how the functional specificity of the GM correlates with certain environment and lifestyle factors and how complexity from the exogenous environment can be balanced by endogenous homeostasis. The Hadza gut metagenome structure allows us to appreciate the co-adaptive functional role of the GM in complementing the human physiology, providing a better understanding of the versatility of human life and subsistence.
Allomaternal assistance, investment provided to children by caregivers other than the biological ... more Allomaternal assistance, investment provided to children by caregivers other than the biological mother, occurs cross-culturally in varying degrees. Allomothering, which consists of caregiving and/or provisioning, can increase the survival of children and the fertility of the mother. Allomothers, who may be related or unrelated to the child, provide care because they receive either direct or indirect benefits. Fathers and grandmothers, who represent a special category of helper and consistently provide the greatest amount of high-investment allomaternal care, show a marked decrease in sex steroid hormones and sexual activity. The sexuality of the recipient mother may also be affected by the presence of allomothers, whether in the form of relatives, a nanny, a babysitter, or a play date—all options alleviate the time constraints of the mother and allow her to invest in other activities, including time for her partner.
It has been suggested that honey may have been an important food source for early members of the ... more It has been suggested that honey may have been an important food source for early members of the genus Homo, yet the importance of meat and savanna plant foods continue to be stressed as the most relevant foods in dietary reconstructions. Here, the importance of honey and bee larvae in hominin diets is explored. Ethnographic reports, examples of Paleolithic rock art, and evidence from non-human primates are used to show that early hominins likely targeted beehives using the Oldowan tool kit. The consumption of honey and bee larvae likely provided significant amounts of energy, supplementing meat and plant foods. The ability to find and exploit beehives using stone tools may have been an innovation that allowed early Homo to nutritionally out-compete other species and may have provided critical energy to fuel the enlarging hominin brain.
Human Nature-an Interdisciplinary Biosocial Perspective, 2008
Cooperative child care among humans, where individuals other than the biological mother (allomoth... more Cooperative child care among humans, where individuals other than the biological mother (allomothers) provide care, may increase a mother’s fertility and the survivorship of her children. Although the potential benefits to the mother are clear, the motivations for allomothers to provide care are less clear. Here, we evaluate the kin selection allomothering hypothesis using observations on Hadza hunter-gatherers collected in ten camps over 17 months. Our results indicate that related allomothers spend the largest percentage of time holding children. The higher the degree of relatedness among kin, the more time they spend holding, supporting the hypothesis of nepotism as the strongest motivation for providing allomaternal care. Unrelated helpers of all ages also provide a substantial amount of investment, which may be motivated by learning to mother, reciprocity, or coercion.
Human prosociality is one of the defining characteristics of our species, yet the ontogeny of alt... more Human prosociality is one of the defining characteristics of our species, yet the ontogeny of altruistic behavior remains poorly understood. The evolution of widespread food sharing in humans helped shape cooperation, family formation, life history, language, and the development of economies of scale. While the behavioral and ecological correlates of food sharing among adults are widely studied, very little is known about food sharing among children. Here, in the first study to analyze the food sharing patterns of hunter-gatherer children, we show that while sharing may be biased towards kin, reciprocity characterizes the majority of all sharing dyads, both related and unrelated. These data lend support to the recent claim that discrimination among kin might be linked with reciprocal altruism theory. Furthermore, we show that age positively correlates with an increase in sharing, both in frequency and amount, supporting recent suggestions that prosocial behaviors and egalitarianism develop strongly in middle childhood when children acquire the normative rules of their society.
Through human microbiome sequencing, we can
better understand how host evolutionary and ontogenet... more Through human microbiome sequencing, we can better understand how host evolutionary and ontogenetic history is reflected in the microbial function. However, there has been no information on the gut metagenome configuration in hunter-gatherer populations, posing a gap in our knowledge of gut microbiota (GM)-host mutualism arising from a lifestyle that describes over 90% of human evolutionary history. Here, we present the first metagenomic analysis of GM from Hadza hunter-gatherers of Tanzania, showing a unique enrichment in metabolic pathways that aligns with the dietary and environmental factors characteristic of their foraging lifestyle. We found that the Hadza GM is adapted for broad-spectrum carbohydrate metabolism, reflecting the complex polysaccharides in their diet. Furthermore, the Hadza GM is equipped for branched-chain amino acid degradation and aromatic amino acid biosynthesis. Resistome functionality demonstrates the existence of antibiotic resistance genes in a population with little antibiotic exposure, indicating the ubiquitous presence of environmentally derived resistances. Our results demonstrate how the functional specificity of the GM correlates with certain environment and lifestyle factors and how complexity from the exogenous environment can be balanced by endogenous homeostasis. The Hadza gut metagenome structure allows us to appreciate the co-adaptive functional role of the GM in complementing the human physiology, providing a better understanding of the versatility of human life and subsistence.
Allomaternal assistance, investment provided to children by caregivers other than the biological ... more Allomaternal assistance, investment provided to children by caregivers other than the biological mother, occurs cross-culturally in varying degrees. Allomothering, which consists of caregiving and/or provisioning, can increase the survival of children and the fertility of the mother. Allomothers, who may be related or unrelated to the child, provide care because they receive either direct or indirect benefits. Fathers and grandmothers, who represent a special category of helper and consistently provide the greatest amount of high-investment allomaternal care, show a marked decrease in sex steroid hormones and sexual activity. The sexuality of the recipient mother may also be affected by the presence of allomothers, whether in the form of relatives, a nanny, a babysitter, or a play date—all options alleviate the time constraints of the mother and allow her to invest in other activities, including time for her partner.
It has been suggested that honey may have been an important food source for early members of the ... more It has been suggested that honey may have been an important food source for early members of the genus Homo, yet the importance of meat and savanna plant foods continue to be stressed as the most relevant foods in dietary reconstructions. Here, the importance of honey and bee larvae in hominin diets is explored. Ethnographic reports, examples of Paleolithic rock art, and evidence from non-human primates are used to show that early hominins likely targeted beehives using the Oldowan tool kit. The consumption of honey and bee larvae likely provided significant amounts of energy, supplementing meat and plant foods. The ability to find and exploit beehives using stone tools may have been an innovation that allowed early Homo to nutritionally out-compete other species and may have provided critical energy to fuel the enlarging hominin brain.
Human Nature-an Interdisciplinary Biosocial Perspective, 2008
Cooperative child care among humans, where individuals other than the biological mother (allomoth... more Cooperative child care among humans, where individuals other than the biological mother (allomothers) provide care, may increase a mother’s fertility and the survivorship of her children. Although the potential benefits to the mother are clear, the motivations for allomothers to provide care are less clear. Here, we evaluate the kin selection allomothering hypothesis using observations on Hadza hunter-gatherers collected in ten camps over 17 months. Our results indicate that related allomothers spend the largest percentage of time holding children. The higher the degree of relatedness among kin, the more time they spend holding, supporting the hypothesis of nepotism as the strongest motivation for providing allomaternal care. Unrelated helpers of all ages also provide a substantial amount of investment, which may be motivated by learning to mother, reciprocity, or coercion.
Uploads
Papers by Alyssa N Crittenden
humans helped shape cooperation, family formation, life history, language, and the development of economies of scale. While the behavioral and ecological correlates of food sharing
among adults are widely studied, very little is known about food sharing among children. Here, in the first study to analyze the food sharing patterns of hunter-gatherer children, we
show that while sharing may be biased towards kin, reciprocity characterizes the majority of all sharing dyads, both related and unrelated. These data lend support to the recent claim
that discrimination among kin might be linked with reciprocal altruism theory. Furthermore, we show that age positively correlates with an increase in sharing, both in frequency and amount, supporting recent suggestions that prosocial behaviors and egalitarianism develop strongly in middle childhood when children acquire the normative rules of their society.
better understand how host evolutionary and ontogenetic
history is reflected in the microbial function.
However, there has been no information on the gut
metagenome configuration in hunter-gatherer populations,
posing a gap in our knowledge of gut microbiota
(GM)-host mutualism arising from a lifestyle
that describes over 90% of human evolutionary history.
Here, we present the first metagenomic analysis
of GM from Hadza hunter-gatherers of Tanzania,
showing a unique enrichment in metabolic pathways
that aligns with the dietary and environmental factors
characteristic of their foraging lifestyle. We found
that the Hadza GM is adapted for broad-spectrum
carbohydrate metabolism, reflecting the complex
polysaccharides in their diet. Furthermore, the Hadza
GM is equipped for branched-chain amino acid
degradation and aromatic amino acid biosynthesis.
Resistome functionality demonstrates the existence
of antibiotic resistance genes in a population with little
antibiotic exposure, indicating the ubiquitous
presence of environmentally derived resistances.
Our results demonstrate how the functional specificity
of the GM correlates with certain environment
and lifestyle factors and how complexity from the
exogenous environment can be balanced by endogenous
homeostasis. The Hadza gut metagenome
structure allows us to appreciate the co-adaptive
functional role of the GM in complementing the human
physiology, providing a better understanding
of the versatility of human life and subsistence.
humans helped shape cooperation, family formation, life history, language, and the development of economies of scale. While the behavioral and ecological correlates of food sharing
among adults are widely studied, very little is known about food sharing among children. Here, in the first study to analyze the food sharing patterns of hunter-gatherer children, we
show that while sharing may be biased towards kin, reciprocity characterizes the majority of all sharing dyads, both related and unrelated. These data lend support to the recent claim
that discrimination among kin might be linked with reciprocal altruism theory. Furthermore, we show that age positively correlates with an increase in sharing, both in frequency and amount, supporting recent suggestions that prosocial behaviors and egalitarianism develop strongly in middle childhood when children acquire the normative rules of their society.
better understand how host evolutionary and ontogenetic
history is reflected in the microbial function.
However, there has been no information on the gut
metagenome configuration in hunter-gatherer populations,
posing a gap in our knowledge of gut microbiota
(GM)-host mutualism arising from a lifestyle
that describes over 90% of human evolutionary history.
Here, we present the first metagenomic analysis
of GM from Hadza hunter-gatherers of Tanzania,
showing a unique enrichment in metabolic pathways
that aligns with the dietary and environmental factors
characteristic of their foraging lifestyle. We found
that the Hadza GM is adapted for broad-spectrum
carbohydrate metabolism, reflecting the complex
polysaccharides in their diet. Furthermore, the Hadza
GM is equipped for branched-chain amino acid
degradation and aromatic amino acid biosynthesis.
Resistome functionality demonstrates the existence
of antibiotic resistance genes in a population with little
antibiotic exposure, indicating the ubiquitous
presence of environmentally derived resistances.
Our results demonstrate how the functional specificity
of the GM correlates with certain environment
and lifestyle factors and how complexity from the
exogenous environment can be balanced by endogenous
homeostasis. The Hadza gut metagenome
structure allows us to appreciate the co-adaptive
functional role of the GM in complementing the human
physiology, providing a better understanding
of the versatility of human life and subsistence.