This study offers a preliminary exploration into the relationships between demography and childcare. Most of the hypotheses presented in this paper are are not formally tested, but are examined using previous research. These hypotheses should be used to inform future research. One hypothesis tested using limited data found that male biased sex ratios are likely to exist in societies where males contribute more calories to the diet than females.

This study evaluates recent research on the roles of fathers in child development in hunting-gathering, simple farming, and pastoral communities around the world. The authors review previously conducted studies as well as highlight the varying theoretical approaches that many of these previous studies have taken.

Genetic, linguistic, and geographic data can be used to explain the distribution of cultural units ("semes") and to understand the evolutionary mechanisms of culture. Three broad models of cultural transmission attempt to explain why cultures share semes: (1) Cultural diffusion, emphasizing horizontal transmission. (2) Local adaptation, where trail-and-error learning leads to the independent adoption of semes by different peoples living in similar environments. (3) Demic diffusion, which emphasizes vertical and frequency-dependent transmission. Authors test the explanatory power of each model using cultural, genetic, linguistic and geographic data from 36 African cultures.

Genetic, linguistic, and geographic data can be used to explain the distribution of cultural units ("semes") and to understand the evolutionary mechanisms of culture. Three broad models of cultural transmission attempt to explain why cultures share semes: (1) Cultural diffusion, emphasizing horizontal transmission. (2) Local adaptation, where trail-and-error learning leads to the independent adoption of semes by different peoples living in similar environments. (3) Demic diffusion, which emphasizes vertical and frequency-dependent transmission. Authors test the explanatory power of each model using cultural, genetic, linguistic and geographic data from 36 African cultures.

Genetic, linguistic, and geographic data can be used to explain the distribution of cultural units ("semes") and to understand the evolutionary mechanisms of culture. Three broad models of cultural transmission attempt to explain why cultures share semes: (1) Cultural diffusion, emphasizing horizontal transmission. (2) Local adaptation, where trail-and-error learning leads to the independent adoption of semes by different peoples living in similar environments. (3) Demic diffusion, which emphasizes vertical and frequency-dependent transmission. Authors test the explanatory power of each model using cultural, genetic, linguistic and geographic data from 36 African cultures.

Genetic, linguistic, and geographic data can be used to explain the distribution of cultural units ("semes") and to understand the evolutionary mechanisms of culture. Three broad models of cultural transmission attempt to explain why cultures share semes: (1) Cultural diffusion, emphasizing horizontal transmission. (2) Local adaptation, where trail-and-error learning leads to the independent adoption of semes by different peoples living in similar environments. (3) Demic diffusion, which emphasizes vertical and frequency-dependent transmission. Authors test the explanatory power of each model using cultural, genetic, linguistic and geographic data from 36 African cultures.

Considerable variation has been observed in allomaternal nursing (breast-feeding by individuals other than mothers) behavior across contemporary foraging populations: while relatively common in some populations, it is rare or absent among others. Here the authors examine data on allomaternal nursing from 12 previous studies of foraging societies and utilize a worldwide sample of 104 cultures to assess global variation in allomaternal nursing.

Considerable variation has been observed in allomaternal nursing (breast-feeding by individuals other than mothers) behavior across contemporary foraging populations: while relatively common in some populations, it is rare or absent among others. Here the authors examine data on allomaternal nursing from 12 previous studies of foraging societies and utilize a worldwide sample of 104 cultures to assess global variation in allomaternal nursing.

Considerable variation has been observed in allomaternal nursing (breast-feeding by individuals other than mothers) behavior across contemporary foraging populations: while relatively common in some populations, it is rare or absent among others. Here the authors examine data on allomaternal nursing from 12 previous studies of foraging societies and utilize a worldwide sample of 104 cultures to assess global variation in allomaternal nursing.

Considerable variation has been observed in allomaternal nursing (breast-feeding by individuals other than mothers) behavior across contemporary foraging populations: while relatively common in some populations, it is rare or absent among others. Here the authors examine data on allomaternal nursing from 12 previous studies of foraging societies and utilize a worldwide sample of 104 cultures to assess global variation in allomaternal nursing.