Their Cognition

If you are reading this, you probably live on earth, or have ancestors who did. You (or your ancestors) have a nervous system made up of hundreds of billions of neurons. The signals they transmit through their trillions of connections are responsible for your memories, your feelings, your beliefs, and your desires. The entire vivid and colorful experience of your mental life arises from electrical activity in populations of these cells. Your memories, instincts, decisions and habits are all encoded in the networks of links between these populations of cells, and between your brain cells and the rest of your body.

How did this happen? It all started with cell specialization. Once cells on earth started working together to form multicellular organisms, they also began to evolve to have specific roles: some cells were hard and protective, others were flexible and could help to move the organism around, and other cells became especially sensitive to certain features in the environment. Photo-sensitive cells would react to light with chemical changes that would pass into the surrounding cells. These chemical changes became a kind of “signal”: like an alarm that would go off any time light was hitting the photo-sensitive cell. This chemical alarm would get passed from one cell to another, and eventually might trigger a chemical response in an especially flexible cell to make it twitch in just the right way that it would move the organism toward the light. And so, you have “stimulus” and “response”.

Over billions of generations, this arrangement became more complex, and cells became even more specialized. Soon enough, there are cells specialized to generate electro-chemical signals in response to pressure, and others that generate signals in response to different wavelengths of light, and still others that generate signals in response to various chemicals found in food. All of them send signals on to other cells, which in turn send signals to other cells, which eventually cause changes in the shapes of cells in the organism in a way that we call “behavior”.

You’ve probably already realized that we have reached the “nervous system” chapter in our evolutionary story. But what about the next chapter? What about thinking?

Intelligence on GJ-1214b evolved very differently.