Natasha, a chimpanzee who lives on an island sanctuary in Uganda, is remarkably smart. What can she do? She can spray water on people. She can throw a stick at an electrified fence to know if it is passing current. She can draw people’s attention by clapping her hands. Ingenious behaviours, by chimp standards. The media lionizes Natasha as the “genius chimp” and the “primate prodigy”. However, can she compose a musical score? Or even a simple poem? Can she write a letter or read a book? No, not even close. The cognition gap between the smartest chimp and even the average human is so vast that it seems incredible that chimps are, in fact, our closest cousins on the tree of evolution. Going back about 6 million years, humans and chimps had one common ancestor. Since then, our ancestors won the evolutionary lottery. There was a point in evolutionary history when it was still an open question whether the human branch or the chimpanzee branch would evolve to dominate the planet. The human branch of the tree was barely distinguishable from the ancestors of chimps. However, some half a million years ago, something happened that triggered the seeming miracle of evolution that resulted in us – Homo Sapiens (Sapiens is derived from the Latin word “sapere” which means – to be wise). From sharing a common ancestor, we have reached a stage where the story of chimps as smart as humans is improbable enough to qualify as the plot for a Hollywood production. So, what accidents brought us here?
Given where we have reached in our development as a species, it is easy to imagine that there was some evolutionary big-bang event that launched us on this trajectory. However, evidence points more towards a series of small steps for the human branch. More like an evolutionary crawl, if you may, away from the chimp branch of the tree. Even as recently as a few million years ago, there were remarkably few anatomical specializations that would have portended greatness for the human branch. Cranial capacity was comparable. If bipedality is an advantage, the chimp branch could handle that as well.
Between one and half-a-million years ago, a series of small evolutionary steps led to a tipping point after which the florid expansion of humanoid capability and capacity took place. This was a period during which the humanoid brain expanded fourfold in volume—from about 350 cc to 1350 cc. Growth in brain capacity may have, in a virtuous and never-ending cycle of use and adaptation, expanded our capabilities, which today include the ability to create synthetic computing machines far exceeding the human brain in capacity and capability. Despite billions of years of life on planet earth, it is interesting that the evolution of a species as sapient as us has happened only once. No other species has followed our evolutionary path. What role might sleep have played in this development?