Thursday, April 16, 2009

How Evolution Can Lead to Consciousness

How could an inanimate, "unthinking" process such as evolution lead to consciousness? A most worthy question.

Really, thought is a tool that can enhance the chances of survival - like sight, heart, and lungs. Thought is really just awareness of one's environment, being able to sense and respond in a way that enables you to find food, or to evade becoming food.

In the competitive maelstrom of evolution, awareness is quite a useful tool - the basic plan of our brain evolved quite early, with Cephalaspis.

For Cephalapsis, it was used as a way to avoid getting eaten.

Our brains are an extension of that basic plan. But, why are we in particular so smart?

Because that is our main tool for survival. Other animals have sharp teeth, fast legs, flight, etc - and those work just fine for them. They are intelligent as well, just not like us.

Being so convinced of our utter uniqueness masks the fact that we are in fact evolved from lower life-forms, that though they are not as smart as us, have the same basic brain-plan as us.

This is an extremely interesting article that explores this:
Animal Intelligence and the Evolution of the Human Mind
Subtle refinements in brain architecture, rather than large-scale alterations, make us smarter than other animals volved
Key Concepts:
* The human brain lacks conspicuous characteristics—such as relative or absolute size—that might account for humans’ superior intellect.
* Researchers have found some clues to humanity’s aptitude on a smaller scale, such as more neurons in our brain’s outermost layer.
* Human intelligence may be best likened to an upgrade of the cognitive capacities of nonhuman primates rather than an exceptionally advanced form of cognition.

In "Walking with Cavemen", part of that series explores the contrast between homo habilis and Paranthropus Boisei. The latter had a larger jaw, and could munch on the tough grass abundant in Africa at the time. Even during the dry season, boisei had abundant food. Habilis, on the other hand, had a much tougher time of it, didn't have the jaw structure to chow down on that, so it pursued a diversity of food sources. with-cavemen-playlist-autoplay.html

When the environment changed, Boisei couldn't adapt, and became extinct. Boisei was overspecialized, in other words. Habilis, on the other hand, was more adaptable, not least because of its larger brain, and survived.

That series also explores how bipedalism led to changes in our chest and such, that led to the possibility of speech, of which Homo Ergaster seems to have been the first to possess. So bipedalism was important, and the main evolutionary selector for this seems to be that as the savannahs expanded in Africa, we could leave our tree-swinging ways. And bipedalism has a tiny energy advantage when walking around in a treeless environment, that over a lifetime might lead to, say, having one extra baby.

With the Homo Ergaster video, it talks about how we "stared our way" into intelligence. As intelligence became our primary survival strategy, it increased over time, favored by natural selection. This is perhaps not too different from the evolution of saber teeth in some big cats. As our intelligence increased, other things, such as our teeth, claws, etc, decreased, which in turn made the intelligence more important as a survival strategy.

After a certain point, especially after we developed the whites of our eyes and hence became more "expressive", much of our increasing intelligence seems to have been a result of needing to understand each other. One can see how this might lead to sort of an "arms race" of expanding brain capacity, as we needed to understand other humans, who were also increasing in intelligence.

The series explores the many accidents of history that made possible the circumstances that eventually led to the rise of human intelligence. For example, when India collided into Asia 8 million years ago, dramatically changing weather patterns. This made Africa drier; up to then, it was pretty much coast to coast forest; after that, the savannah opened up, making moving out of the trees and bipedalism a successful path for our ancestors to take.

Really, the number of unusual circumstances are pretty substantial that led to the rise of our intelligence. To me at least, there was nothing inevitable about it. And considering our brand of intelligence is the only time it has been pursued in 4.5 billion years is one of the main reasons I suggest other advanced alien civilizations might be quite rare.

However, the main point here is that when you look at awareness and consciousness as useful tools for surviving and thriving, and hence in the right circumstances favored by evolution, it is not so mysterious as to how it could have occurred.

But I agree with the thrust of this thread, our brains are damned amazing. But God or aliens are not required to explain them.

This is an interesting article on some of the many artifacts of our fish and amphibian origins still with us today:
Key Concepts:
* Routing of nerves and fluid pathways in the human body resembles the tangle of wiring and pipes in an aging house, a heritage from fish and amphibian ancestors.
* The tube through which sperm passes forms a roundabout loop that can lead to hernias, a result of major anatomical changes that occurred as we evolved from fish.
* Nerves that are inherited from fish and travel from the brain to the diaphragm can become irritated and trigger hiccups, a closing of the entryway to the windpipe, an action that itself is a hand-me-down from amphibians that breathe with both lungs and gills.

This article has really got me thinking:
How to Save New Brain Cells in-cells
Fresh neurons arise in the adult brain every day. New research suggests that the cells ultimately help with learning complex tasks—and the more they are challenged, the more they flourish

The studies were done in mice, and it was shown that their brains produce between 5,000 and 10,000 new neurons a day, even in adult brains. It is extremely likely that something similar occurs in most animal brains, at least most mammals.

We don't know what the numbers are for humans. However, as a wild guess, it would not seem unreasonable to suggest that in humans we might generate 10 times this number as that of mice - perhaps 50,000 to 100,000 fresh neurons a day.

This reflects great evidence of the plasticity of even the adult brain of most animals. In the case of humans, with our nominally greater intelligence, we can begin to understand how such plasticity can accommodate things like the structures of civilization, religion, law, as well as technology.

Interesting thing about religious belief. In the Walking with Caveman video entitled "Walking with Cavemen - Part 4 Survivors 1 of 3", available from the Caveman link above, it discusses Homo Heidelbergensis, who lived in Europe about 500,000 years ago. They were quite similar to us in many ways, but they did not have the conception of an afterlife, and hence, presumably no religious beliefs in general. So our capacity for religious belief, or need thereof, came some time afterwards.

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