Death Rate
When death rates were much higher, a culture’s ability to impart behaviors that reduced odds of death granted it a significant advantage. Consider Islamic ritual purification, Wuḍū, which involves washing one’s face, hands, and feet with clean water (e.g., it is OK to use water from melted snow but not water that may have touched urine or a dead animal). It is hard to argue that, all other things controlled for, a culture that had its adherents washing five times a day would not have a lower death rate than other cultures in a pre-germ-theory era. It’s wild to think that this knowledge was imparted through cultural evolution into a tribe of desert nomads (and later adopted by Islam) centuries before Joseph Lister and Ignaz Semmelweis arrived at this knowledge through science.
Some cultures evolved and adopted practices that helped adherents survive in specific conditions, such as desert environments or hostile frontier landscapes (consider Inuits, who developed a culture enabling them to live in extremely cold environments[[71]](#_ftn71)). Essentially, these cultures evolved traditions that allowed them to thrive within specific environmental or societal niches considered too hostile to other cultures.
Even though death rates are much lower now than they used to be, modern cultures can still secure a competitive advantage by imparting healthy habits to adherents. A culture less likely to be plagued with obesity and addiction will outcompete an otherwise identical culture that lacks these defenses.