When I was young, my father revealed to me a twisted truth that blew my mind. “You know,” he said, “the brain named itself.” The more you think about it, the stranger this fact becomes. The brain is on the job 24/7, even when we sleep. It is the ultimate multitasker, managing sensation, breathing, memory, language, emotions, logic and more all at once. The brain has more cell types than any other tissue in the human body. When scientists study the brain, they must make decisions about their particular focus — psychology, physiology, chemistry, etc. — because the brain’s different compartments and functions are too complicated to conquer all at once. All this, for one organ.
The truth is, scientists are still confounded by the brain. It is full of ridges and trails that remain an uncharted territory, and even when we have a map for our brain, we still don’t know why the brain performs some of its fundamental activities. For example, scientists don’t really know why we sleep (1). We, along with most animals, will spend about a third of our lifespans asleep. For an animal in the wild, risking your own life, or at least the lives of your progeny, to lay down and rest hardly seems practical. Nevertheless, sleep is universal to most living beings. Countless studies note the consequences of sleep deprivation and others have meticulously mapped the areas of the brain that turn on and off while we are asleep. Theories on why we sleep include giving the brain time to strengthen neural networks while destroying those that are no longer needed (2). Still, scientists have yet to agree on a definitive explanation for our sleep.
So let’s talk about brains. They’re complicated. And mysterious. Every day, people use their brains to learn more about themselves and the universe. We have countless labs devoted to the study of this single organ. This very website features the brain and mind in its articles more than any other subject. Since our brains are responsible for plenty of amazing discoveries and creations, we naturally take pride in our phenomenal brains. However, the rest of the universe may not care as much about brains as we do, sometimes not even our own cells.
When an egg is fertilized, the embryo sets aside about 40 germ cells that will reside in its gonads to later create its own offspring. Once they are formed, they migrate together in an assembly line through the embryo’s tissues to the gonadal ridge, the area marked for the gonads (3). The important idea here is that, during the first 24 days of existence, the organism’s cells are not even slightly interested in making a brain (or even a heart!). Rather, they care only about making more. This phenomenon has led scientists to speculate that an organism’s fundamental goal is reproduction, and the brain, heart — what we recognize as life, really — are all just the means of aiding an end.
This theory makes sense when we think about all the living things on our planet that that thrive without a brain. Consider plants; not only can they make their own food without a brain, but perhaps they can also have anthropomorphized traits such as hearing and learning capabilities without one. In the RadioLab episode titled, “Smarty Plants,” evolutionary ecologist Monica Gagliano, who had made the same seemingly outrageous proposals, conducted a number of experiments on the mimosa pudica, also known as the sensitive plant (4). Remarkably, when an herbivore comes into contact with the mimosa, it curls in all its leaves to resemble nothing more than an untasty stem or twig. After loading this sensitive plant into an original dropbox apparatus, Gagliano would let the plant free-fall about eight inches onto a cushioned surface. Naturally, the moment the plant touched the ground, it would curl in on itself. However, as Gagliano repeated this experiment, the plant continued to land on the ground but stopped curling in on itself, as if it had realized that this fall would not bring it any harm.
Scientists were blown away by these results. How could the plant possibly remember that this activity would not bring danger? It does not have a brain so it cannot have a memory. Some theorized that the plant’s biological functions were simply exhausted after so many falls and that it stopped folding because its energy was depleted. However, when Gagliano performed the same experiment on a plant that had “learned” the fall was harmless after leaving the plant undisturbed for three whole days, the plant “remembered” and still did not fold in on itself.
I once participated in a conversation in class about whether or not vegans should be unwilling to consume scallops because they lack brains and are therefore no more intelligent than plants (5). This conclusion, however, is based on the assumption that brains are necessary for intelligence. I think because we, as humans, attribute so much of our accomplishments and trials to our brains, our worldview is primarily brain-centered. It is our brain, after all, that makes us wonder about intelligence in the first place.
Perhaps intelligence is not unique to humans, or any animal with a brain for that matter. Indeed, for all the hype we give our incredible brains, we still can’t figure out how some of these organisms manage without one. If we expand our notion of intelligence, we see how interesting and complex the brainless beings with whom we share our planet truly are. And by challenging our bias towards brains, we may learn and discover more than we — or rather, our brains — could have ever imagined.