Posted on Dec 02, 2019, 5 p.m.
As many sit in recovery from the days of excess at the dinner table over the weekend here’s something else to take into consideration the next time you think about what to be thankful for, and this applies to all humanity: the evolutionary journey that provide you that big beautiful brain and your longevity.
All this comes courtesy of our primate ancestors that invented cooking over a million years ago; you are fortunate to be a member of the one species that was able to afford so many cortical neurons in its brain, with them comes extended childhood and long lifespan which makes human beings unique.
Benefits of the bigger brain cortex means that several generations of your family can gather around together at the same time to exchange banter, share information, and gossip, then your wonderful brain takes all of that information and turns it into knowledge and and lets you practise the subtleties and art of what not to say and when not to.
Another achievement of being blessed with our neuron laden human cortices is the ability to create which has brought forth all the technology that allows people to spread all around the globe to be able to come together via various methods of transportation to screens or through words whispered over long distances traveled to our ears. Although some argue this technology may bring people together it is also driving people apart, and they aren’t exactly wrong.
6 in 10 educated people believe that humans only use 10% of our brains, but we actually use all of it, just in different ways at different times according to neuroscience research. This myth seems to be supported by textbooks and scientific articles that also say “the human brain is made up of 100 billion neurons and 10 times as many supporting glial cells.”
Neuroscientists at the time didn’t know if those were the actual numbers of cells in the human brain, but they did have a rough idea; some suggested 10-20 billion neurons in the human cerebral cortex while others suggested some 60-80 billion in the cerebellum with the rest of the brain being known to be fairly sparse in comparison. The number of neurons in the entire human brain is definitely closer to 100 billion that 10 billion, but too far from 1 trillion.
Neuroscientists were armed with fancy gadgets and cutting edge tools to modify genes in order to light up parts of the brain at the time, but even with the illumination they were still in the dark over what different brains were made of and how human brains compared to others.
Suzana Herculano-Houzel, CC BY-ND, who is proposing we revise the way humans tell the story of how our species came to be, devised a way to rapidly count how many cells a brain is made of; spending 15 years collecting brains and examining them under a microscope; she determined there are many ways to put brains together. Primates have more neurons in the cerebral cortex than other mammals regardless of brain size just as humans; a large brain can be made of relatively few neurons if they are huge as in an elephant, while primate neurons are small and bird neurons are even smaller. Even the smallest bird brain can contain many neurons, but never as many as the largest primate brain which is the human brain.
When comparing brains we focus on the number of neurons in the cortex because this is the brain region that allows us to go beyond simple detection and responses to stimulation to let us learn from the past and make plans for the future.
In simple terms neurons can be seen as Lego pieces that build brain blocks and process information, the more cortical neurons a species has the more flexible and complex cognition will be regardless of size. It was recently discovered by Herculano-Houzel that the more cortical neurons there are the longer the species will take to develop into adulthood just as it would take longer to assemble Legos into a mansion that into a little cabin; and for unknown reasons along with more cortical neurons come longer longevity.
Having more cortical neurons seems to be a 2 for 1 bargain; evolve more mental capabilities and get the bonus of more lifetime to learn, develop, and use the abilities. However, having lots more neurons cost a lot more energy, the brain is greedy that way.
If humans had exclusively kept to eating raw foods as all other primates do we would need to have spent over 9 hours every single day searching, collecting, and eating to feed their some 16 billion cortical neurons. When you look at it that way you can most likely forget about ever discovering electricity or inventing and building airplanes as there would have been no time for idling looking up at the stars to wonder what could be.
Our great ape cousins, being raw food eaters, have at most half as many cortical neurons as humans do, and they eat for over 8 hours a day. Human ancestors figured out how to cheat nature and get more from less via the first stone tools and fire later in time, cooking food was invented which changed history. Eating is now faster and more efficient when food is pre-processed and transformed with fire adding the benefit of deliciousness.
Now with plenty of calories being available in far less time generations went on to develop bigger and better brains, the more cortical neurons they had the longer their offspring remained kids, and the longer parents lived with the former learning more from the latter, then with time learning from grandparents, and with passing time even learning from great grandparents. Soon cultures began to flourish, followed by technology blooming and living on through schooling and science to become ever more complex creatures.
People have so much culture to share, what makes modern humans has become about more than human biology. Being fortunate enough to have evolved to be born with lots of neurons gives humans the potential for a long and slow life, one where the brain has the opportunity to be educated by what previous generations have learned, and to educate future generations. People will remain modern humans as long as we are willing to gather together either at the dinner table or at events to celebrate our differences, share hard earned knowledge, stories of success/failure, hopes/dreams, and are open to learn from each other. So much more can be accomplished on this planet if more people were willing to put aside differences and quests for power to use those big beautiful brains and come up with solutions to pressing issues for the benefit of humankind as a whole.
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