“Ooh! The dress suits you! You’re beautiful!”. “Great Job. You’ll surely top the class!” “I’ve never eaten in a 5-star restaurant that could match up to your excellent cooking!”
These are compliments, and people love to hear them. But when there’s too much, one can tell you, “Stop! You’re giving her or him a big head!”
Setting aside the fact that “giving one a big head” is just an idiom to illustrate the assumption of people’s exaggeratedly high opinion of themselves, there are concepts like Evolution and Genetics.
So, are heads getting bigger and bigger?
It is not apparent, but humans continue to evolve. Because of everyone’s medical uniqueness and differences, some survive while others do not form a given disease or genetic abnormality. Those who remain alive can continue life on Earth and multiply and produce a generation with these genes to help them in circumstances that endanger them. In this way, natural selection persists.
Evolutionary geneticists affirm that Homo Sapiens humans, are still evolving along with other animals and plants. Because of constant change in the environment, from climate change to access to resources, everyone – humans, animals, and plants – respond differently.
Based on the latest forensic research, skulls of Americans (and perhaps those of other nationalities) have increased in length and space. The director of Milner Centre of Evolution at the University of Bath, Laurence Hurst, claims that several current examples can connect to human evolutionary change, which often is related to geographic variance and regional isolation.
An example of human evolutionary change would be the Bajau People of Indonesia, who rely on their traditional marine lifestyle to feed their community. For thousands of years, most of their time is spent in or by the ocean, and so the Bajaus have developed diving skills that allow them exceptional ability to hold in their breath for long periods. According to Melissa Ilardo, a genomicist, a physiological examination revealed that the Bajau had uniquely large spleens that were 50% bigger than that of mainland Indonesians. This is because, as humans deep-dive, pressure increases, and the spleen contracts in response. Since the spleen holds oxygenated blood, when it contracts, red blood cells are pushed into the system, giving an oxygen boost.
Let’s return to the topic centered on the Human head getting larger. It’s helpful to recall the history of the Skull. When the first Homo sapiens emerged until 30,000 years ago, the human brain went from an increasing trend to that of plateauing head size. When agriculture was centralized in the lives of humans from 5,000 to 6,000 years ago, skulls started to shrink. The explanation for this decrease in skull size has been debated, but multitudes point to the fact that agriculture has given humans a leeway and a lack of necessity for being smart to survive.
Around 2002, a group of Anthropologists – Lee Jantz, coordinator of UT’s Forensic Anthropology Center (FAC), Richard Jantz, former director of FAC and Joanne Devlin, assistant professor- examined 1500 skulls dating back to mid-1800s to mid-1900s. Their research has implied that skulls have become larger, taller, and narrower (from front view) and that faces have become significantly narrower and higher. They also noted that with human’s growing obesity rates, the skeletal shape could be affected. However, this study was limited to skulls from American and European adults because they were more readily available.
This can be almost no surprise because, throughout human evolution, brain size tripled. Compared to other living primates, modern humans possess the largest and most complex brains. The current average brain weighs 1, 352 grams while that of a chimpanzee, the closes relative, weighs at 384 grams. Large brains mean larger heads. Larger heads equate to more difficult childbearing.
A research team’s results were published in the Proceedings of the National Academy of Sciences. It revealed statistical evidence on the increase in mothers having C-sections to deliver babies over the past decades. This shows the evolutionary change that while birth canal size remains fixed, babies’ heads are getting bigger.
As humans evolve and change a characteristic or two about themselves for the better, so also must humankind’s drive to embark on research and scientific discovery to provide answers for questions like these. Our heads may get bigger, but so must our perseverance to uncover ways to make each one’s life on Earth better.