For thousands of years, scholars have been theorizing about why human groups structure themselves the way they do, allowing more power and freedom to certain individuals and less to others. This article takes an evolutionist approach to that question, using a variety of mathematical models to predict changes in social organization throughout the evolutionary history of humanity and its ancestors, accounting for changes in brain size and global human populations. The authors validate their models using data from the ethnographic record. In general, they find that tendency towards hierarchy decreases with bigger brain size but increases with global population growth.

The 'obstetrical dilemma' postulates that human females evolved a pelvis shape that was a compromise between the needs of bipedal locomotion and the need for a wider pelvic opening. The implication is that the female pelvis should be similar across the world. Researchers examine the size and shape of the birth canal of female individuals in the Goldman and Human Origin datasets. Contrary to the 'obstetrical dilemma,' the findings reveal that there is indeed significant geographical variation in size and shape of the female birth canal. Neutral evolutionary processes, particularly genetic drift, were suggested to be influential in female canal shape whereas the predicted effects of climate on canal diversity were only minimal.

The 'obstetrical dilemma' postulates that human females evolved a pelvis shape that was a compromise between the needs of bipedal locomotion and the need for a wider pelvic opening. The implication is that the female pelvis should be similar across the world. Researchers examine the size and shape of the birth canal of female individuals in the Goldman and Human Origin datasets. Contrary to the 'obstetrical dilemma,' the findings reveal that there is indeed significant geographical variation in size and shape of the female birth canal. Neutral evolutionary processes, particularly genetic drift, were suggested to be influential in female canal shape whereas the predicted effects of climate on canal diversity were only minimal.

In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.

In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.

In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.

In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.

In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.

In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.

In this article, the authors seek to reevaluate Nolan's (2003) study on the primary determinants of war. They reanalyze his hypotheses with what they claim are more robust measures and methodology. They conclude that there is only a little evidence supporting Nolan's theories, that more productive echnology and higher population density predict war, and that overall ecological-evolutionary and sociopolitical explanations of war are equally supported by empirical data.