The Evolutionary Roots of Human Emotions

Have you ever wished to not feel your emotions? When you feel angry or sad like all human beings do, have you ever wondered why you are feeling certain emotions? This question would lead to another question: Why do humans have feelings? How did emotions even start to exist in humans? To answer these questions, we need to go back to the very beginning of life.

About 250 million years ago, in the region where today’s Siberia is, a significant amount of magma exploded. When the explosion happened, a great amount of carbon dioxide, or CO2 was released into the atmosphere. As an effect of the release of CO2, the temperature of the earth increased, which caused the extinction of numerous ancient organisms. One of the only organisms that survived, Cynodont, was a mammal-like reptile, which evolved to remove its stomach ribs.

At this point, you might wonder: How on earth are the magma explosion and the evolution of mammal-like reptiles related to why we, humans, feel emotions today? Well, let's narrow it down a bit more. Since magma exploded, an enormous amount of CO2 was released, and the oxygen level dropped to 15%, the ancestors of mammals removed their stomach ribs in order to create a body respiration system so that they can breathe in oxygen as much as possible to survive. Because the ancestors of mammals evolved over long periods of time to remove the stomach ribs, they began to have placentas, which is a space in the stomach that can contain their offspring. Because mammals evolved to have placentas in their stomachs, they were able to bear their own babies after holding and protecting them in their stomachs.

Now here comes the origin of human feelings. After mammals evolved to bear their offspring and fed their offspring the milk produced from their own bodies, the emotional linkage between mother and baby began to evolve. Furthermore, since the ancestor of mammals called Eomaia evolved to have molar teeth that can break down food more easily, they evolved to separate their jaws from their skull, which allowed more space in the skull to grow the size of their brains. Since mammals evolved in a way to expand their brain size, they began to have more neurons in their brains which made them able to survive life on earth, and from those mammals, humans evolved from Australopithecus to today’s humans, Homo Sapiens Sapiens.

Since mammals evolved to have a space for babies in their stomachs, and increased their brain size, today’s humans, us, have emotions as a result. And you might still wonder: Why does knowing about the relationship between the evolution of mammals and modern humans’ feelings matter to me? It matters because recognizing how long humans’ emotions have developed helps us understand better about the origin of ourselves, which makes us realize how much the existence of each one of us is a special gift from the past of nature.

Let’s now relate ourselves once more to all the history above by using the ‘if’ statement. If the magma never exploded 250 million years ago, if the oxygen level in the earth’s atmosphere never dropped, if the ancestors of mammals never evolved in a way to remove the stomach ribs, if the mammals never evolved to have placentas in their stomachs which allowed them to contain and protect their babies, we would not be able to feel any emotions now. In fact, humans would not even exist. There would be no humans alive, who can think and feel about the relationship between past, present, and future. Thus, the most meaningful takeaway from this evolution is this key message: “Emotions that we feel today, no matter how good or bad you feel about those emotions, are the results of evolution that happened from the past and went through numerous different possibilities.”