Our Brain and Cognition: Uniquely Human?

Does the stuff of our human brain, its molecular make up and architecture, its genetic prescriptions, uniquely separate us by an evolutionary order of magnitude from the functioning brains of other mammals and life forms? And as a result, does our capability and experience of sentience and cognition likewise separate us by an extraordinary evolutionary advance from any other living creatures? Or is the development of our brain and our cognitive experience just the next predictable or expected evolutionary step in a progression as notable for what we have in common with our closest evolutionary relatives as for what is unique about us and our more advanced abilities?

To most of us--or to me, at least--both propositions seem to have the ring of truth. Why would I have to abandon the second proposition to embrace the first? But this difference of opinion about human uniqueness and the state of human evolution has been the basis for debate among some of our best biolgical, behavioral and cognitive scientists.

The linked article below in Edge is by Prof. Michael Gazzaniga, a leading neuroscientists, Professor of Psychology, and Director of the SAGE Center for the Study of Mind at the University of California Santa Barbara. He provides a readable primer on the background of this research and debate while providing his evolutionary case for the dominance of the first proposition: the uniqueness of our brains and the resulting singular and remarkable level of our cognitive ability. He sets the table by observing that,

It seems that half of the scientific world sees the human animal as on a continuum with other animals and others see a sharp break between animals and humans, see two distinct groups. The argument has been raging for years ...It has always been a puzzle to me why so many neuroscientists become agitated when someone raises the question of whether or not there might be unique features to the human brain. Why is it that one can easily accept that there are visible physical differences that make us unique, but to consider differences in our brains and how they work is so touchy?

The foundation for his position is research evidence for unique human evolutionary advances--positive selection of gene variants, or "phase shifts," as he calls them--that occurred at two points in what he posits is the continuing evolution of man: one approximately 37,000 years ago, and the second only about 5800 years ago. Prof. Gazzaniga suggests the first is coincident with the emergence of culturally modern man, while the second, importantly, appears coincident with the development of agriculture, cities, language and recorded history. But in concluding, he acknowledges the continuing open questions:

This all sounds promising. We’ve got the big brains. Some of those big brains have discovered at least some of the genes that code for the big brains, and the genes appear to have changed at key times in our evolution. Doesn’t this mean they caused it all to happen and that they are what make us unique? What we don’t know is if the genetic changes caused the cultural changes or were synergistic, and even if they did, what exactly is going on in those big brains and how is it happening?

And for those of us called to understand also the spiritual experience and identity of man, we would have to note, and with some importance, that this second "phase shift" also appears roughly coincident with mankind's early spiritual experience, over time leading to the development of personal faith identity and organized religion.

http://www.edge.org/documents/archive/edge242.html