Updated: Mar 26, 2021
A recent study conducted by Southern Illinois University's anthropology professor, Ryan Campbell, highlights a connection between our lifestyles and bone structure.
Through an insightful interview, Professor Campbell introduces new concepts that relate our cultural choices to our bone anatomy.
Discussing the particular topic of human plasticity, where our bodies are able to structurally and biologically change over time, there are many factors that affect who we are today. Campbell discusses the two pillars of his research that play a role in our present selves: biology and culture.
"There are things that our bodies biologically are able to do to compensate for environmental changes," tells Campbell, "and that involves our actual genes."
In our daily lives, our biology allows us to adapt to our surroundings and also determine some of our genetic characteristics. Campbell explains how teeth, for the most part, are canalized, meaning they mainly adhere to our genes. For this reason, teeth generally undergo very little change in their overall appearance and can serve as great sources of observation when making inferences of people and their relatives based on their genetics.
But there is a second layer to our structure that is unrelated to our biology and rather cultural.
Humans are plastic in both a biological and cultural sense, which Campbell acknowledges as the factors that allow them to change over time. With our biology only being able to expand so far when shaping us, culture takes on a new field of interest that serves as an extra layer of adaptability.
In particular, Campbell explores the significance of culture and its connection to bone functional adaptation, the process of bone cells detecting mechanical and pressure signals to make necessary changes in a bone's architecture.
When discussing the daily lifestyles of individuals, Campbell observed the cortex of their leg bones and its relationship to their daily activities. What he found was fascinating in understanding exactly how our actions could affect us biologically.
In comparing those who engage in a lot of physical activity to those who do not, Campbell revealed the importance of bone pressure, which he used to greatly guide his research.
"What we essentially came to understand was that bone cells can sense that slight variation in pressure," explains Campbell, "which causes microfractures in our bones that provide a signal to stimulate additional growth." What this meant was that those who were more physically active had thicker bones due to the additional pressure they were exerting onto themselves.
On the contrary spectrum, in native populations, Campbell acknowledged that sometimes there was very little change in their biology. He could attribute such observations to their continued engagement in traditional practices, such as farming, that allowed them to retain the majority of their culture during a time of immense, cultural growth.
The development of our bone structure is not only limited to our limbs, however. It encompasses a broad variety of bones that Campbell addresses in his other research as well.
Concerning baboon malocclusion and skulls, Campbell observes that increased pressure from chewing harder foods directly impacts the teeth as well as their cranial makeup. Not only do our activities affect who we are, but so do our diets, where the overall concept of bone cell signals and pressure initiate extra growth.
Throughout our bodies, different bones experience different amounts of pressure. When regarding his skull and leg research, Campbell recognizes that the varying amounts of pressure in each bone affect the amount of growth they will experience.
A past study revealed that people who lay down for longer periods of time developed a thicker part of their skull there because of the additional pressure, but the surprise was that the growth was not very uniform. The concentrated bone growth could be connected to the uneven distribution of pressure on that area of the skull that was not as consistent or as widespread as the pressure of our body weight on our legs.
Ultimately, the relationship between cultural pressures and our biological makeup is vast, but Professor Campbell explores it with pride as he uncovers the little secrets to better understand who we are.
So, next time you go out for a jog or bite into an apple, think about how your bones are responding to those actions.
Because you never know what might be happening beyond the surface level of your life, where your bones have their own secrets to share.