Emotions and ritualized behavior patterns are not characteristically human even if they are built deeply into every one and are part of our humanity.
In fact, other animals have feelings, but what distinguishes the humans as species is thought.
We are (each of us, without any exception) largely responsible for what gets put into our brains, for what, as adults, we wind up caring for and knowing about.
The cerebral cortex is a real liberation, as we need no longer be trapped in the genetically inherited behavior patterns of lizards and baboons. No longer at the mercy of the reptile brain, we can change ourselves.
But there is no way for evolution to rip out the ancient interior of the brain because of its imperfections and replace it with something of more modern manufacture. The brain must function during the renovation. That is why our brainstem is surrounded by the R-complex, then the limbic system and finally the cerebral cortex. The old parts are in charge of too many fundamental functions for them to be replaced altogether. So they wheeze along, out-of-date and sometimes counterproductive, but a necessary consequence of our evolution.
Just sixty-five million years ago our ancestors were the most unprepossessing of mammals – creatures with the size and intelligence of moles or three shrews. If a biologist from another star system were to visit the Earth, it would have taken a very audacious scientist to guess that such animals would eventually produce the line that dominates the earth today.
The Earth then was full of awesome, nightmarish lizards – the dinosaurs, immensely successful creatures, which filled virtually every ecological niche. It was populated with swimming reptiles, flying reptiles, reptiles – some as tall as a six-story building, - thundering across the face of the Earth.
Some of these reptiles had rather large brains, a upright posture and two little front legs very much like hands, which they used to catch small, speedy mammals – probably including our distant ancestors – for dinner.
If such dinosaurs had survived, perhaps the dominant intelligent species on our planet today would be four meters tall with green skin and sharp teeth, and the human form would be considered a lurid fantasy of saurian science fiction.
But the dinosaurs did not survive. Because in one catastrophic event all of them and most of the other species on the Earth, were destroyed. It seems that 95% of all the species in the oceans may have died at that time. With such an enormous extinction rate, the organisms of today can have evolved from only a small and unrepresentative sampling of the organisms that lived in late Mesozoic times.
If things had been a little different, it might have been some other creatures whose intelligence and manipulative ability would have led to comparable accomplishments.
Perhaps the smart bipedal dinosaurs, or the raccoons, or the otters, or the squid. It would be nice to know how different other intelligences can be; so we study the whales and the great aps.
Most of the species were destroyed. But not the tree shrews. Not the mammals. They survived. Image: © Megan Jorgensen