MapMorph: Teaching Human Variation

Anthropological Theory in Human Variation


This website is pedagogical tool for understanding what shapes human variation.

We are all familiar with the concept of race. If you look around, you could assign a race label to each person you see. However, if everyone in the room partakes in this same activity, there is high probability that people will be labeled as belonging to more than one race. This is because race is not biological. It is a social label printed on people based on how others perceive them. Race was created by man to establish a hierarchy, or rank, of the human race. This social hierarchy was created using phenotypic traits to draw arbitrary circles around groups of people giving the appearance that these groupings held biological truths.


It is important to first understand the difference between phenotype and genotype. Phenotype is an individual’s observable physical traits resulting from the interaction of their genotype with their direct environment, such as skin color or shape of the nose. Genotype which is an individual’s heritable genetics, or the genes that have been passed from the parents. Phenotype will be the focus of this page given this is what we can easily see with our own eyes and it is what was used to create social race groups throughout history.


In the early 1900s, people like Earnest Hooten and Ales Hrdlichka, two of the earliest physical anthropologists, conducted research that fueled race theory in the United States. Most of Hrdlichka’s work focused on Native American migration and human variation. Hooten’s work focused on creating racial classification systems using phenotypic traits like hair color, size of the skull, and nose shape, amongst others, to label individuals as Caucasoid, Negroid, or Mongoloid. But he went further to describe behavior traits for each race to aid in criminal investigations. This has had serious implications on the legal system as it leads to the belief that people with darker skin would have a greater chance of being a criminal. In Hooten’s hierarchy, he also placed people of African descent as closely related to apes and giving them less social power than European descendants. Additionally, Hooten and Hrdlichka served on the Committee on the Negro which “focused on the anatomy of blacks and reflected the racism of the time” (AAA ref). This committee aided in progressing the eugenics movement, a movement to cleanse the human race through selective breeding by eliminating inheritance of undesirable physical, mental, or moral traits. This means that those seen as delinquents, mentally ill, or physically unfit (e.g. dwarfism) could be sterilized through various forms of medical interventions so they could not reproduce.


These dark times of America’s history have had lasting impacts on our culture, politics, and even biology. The act of scientists dictating to the public that race is real, race is a biological truth, and that we can rank all humans based on their phenotype allowed for the U.S. government to feel justified in creating policies that favored European descendants. This led to those who were not of European descent (e.g. Africans, Native Americas, and Chinese) experienced greater rates of poverty and disease due to limited access to resources driven by policy. This culture of division led to many viewing people outside of their social race as “the other” which impacted mating practices. Traditionally, in the U.S., it is less common for people of different social races to mate and reproduce meaning there has been a low degree of genetic exchange between the groups over time. This mating practice has resulted in lasting phenotypic variation between current social race groups meaning that the original arbitrary boundaries drawn around groups of people have has lasting influence in the population genetic structures in the U.S. These practices have allowed the sociopolitical structures to continue to view social races as separate entities, thus, ensuring differential treatment between the groups.


Let us return now to the term phenotype. Anthropologists understand that there is great phenotypic variation amongst the human race and that an individual’s phenotype is determined by their genome and their environment. The human body is a c omplex organism that can adapt and change in order to survive in its environment. This means that while all humans have the genetic material to make skin, noses, and the same physical form, they have small differences that allow them to live in their environment. For example, people living in cold climate need narrower noses than people living in warmer climates. Narrow noses slow down the rate that air is inhaled so that the body can warm the inhaled air before it reaches the lungs. If the air is too cold when it reaches the lungs, the lungs can be damaged. Because people have moved around the world throughout history, anthropologists recognize that phenotypic traits are expressed a different rates between groups and we can never say that one trait is only represented for a specific group of people or social race. This will be explained in greater detail in the Macromorphoscopic Traits module of this page.


Please explore the page to learn how climate and genetics creates human phenotypic variation. This variation is continuous across the world and phenotypic traits can be expressed in all races. The goal is to demonstrate that while there is human variation based on population histories, there are no definitive boundaries that can assign someone to a specific group. This outdated belief that social race is rooted in biological truths has had many negative social consequences. When we understand why we see physical differences between people around us, we can see that we are all more alike than we are different and we can begin to ease racial tensions in the current sociopolitical climate. Change begins with education.