Among all of our species’ peculiar characteristics, such as bipedalism, practical hairlessness, and unprecedented speaking abilities, intelligence is what distinguishes us Homo sapiens from our hominin relatives the most. Our skulls are relatively unique in that they are largely devoted to thinking rather than food processing. To exemplify this “shifted set of biological priorities,” consider that our cranial vault has expanded at the expense of our jaw. Specifically, our neocortex, a brain region critical for complex cognitive functions such as language and reasoning, has grown significantly. In fact, over the course of human evolution, the human brain has tripled in size, making the modern human brain the largest and most complex of any living primate. Today, our brain accounts for 2% of our body weight and uses 20% of our oxygen & blood flows.
This has all contributed to evolutionary success by allowing early humans to adapt to their environments, manage increasingly advanced social networks, and create complex tools. Homo sapiens' astounding brain growth is hypothesized to have been induced by dietary adaptations such as the ability to cook food with fire and obtain higher-quality nutrients, managing complicated social relationships within large communities, and tool making and usage.
While our relatively large brains allowed us to process and store lots of information, especially during times of great climate change (as shown in the graph below), it is not just about size. Our remarkable intelligence as a species can really be attributed to our brains being largely dedicated to complex cognitive functions, resulting in Homo sapiens having the highest number of cortical neurons and the highest information processing capacity (IPC).
Works Cited
Dicke, Ursula, and Gerhard Roth. "Neuronal factors determining high intelligence." National Library of Medicine, 5 Jan. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC4685590/. Accessed 12 Oct. 2024.
Downey, Greg, and Daniel H. Lende. Evolution and the Brain. 2012. MIT Press Direct, https://doi.org/10.7551/mitpress/9219.003.0006. Accessed 12 Oct. 2024.
"What does it mean to be human? Brains." Smithsonian National Museum of Natural History, humanorigins.si.edu/human-characteristics/brains#:~:text=Large%2C%20complex%20brains%20can%20process,complex%20of%20any%20living%20primate. Accessed 12 Oct. 2024.
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