1. Complex Synapses Drove Brain Evolution

Comment #190772 by Steve Crawley on June 9, 2008 at 2:32 pm

No scientist, I had often wondered what sparked the huge increase in size of human brains.

The following synthesized information that I am sharing with you appeared in one of the TV documentaries recently. It was so interesting that I made these notes in order to remember it. It also gives a few points about how we talk and think with our big brains.

About 2.4 million years ago, a member of the Homo erectus family experienced a mutation in the muscle fabric of the lower jaw. The effect of the mutation was that the muscle fabric cells became much smaller and therefore much weaker. This smaller size as compared to mammals with large bites can be seen in microscopes today. Ordinarily, the combined lower jaw muscle attachments nearly wrap around the sides of the head to ensure a solid footing for a strong bite. The new smaller muscle has a much smaller footprint that did not constrain the growth of the skull, which allowed it to expand to accommodate a larger brain needed to survive. With the loss of the "big bite", this new member had to fight his battles using his brain instead of his brawn. He survived and so did the rest of his progeny who are now known as Homo sapiens.

About 200 to 300 hundred thousand year ago, another mutation occurred in gene FOXP2. The change resulted in the tongue, mouth, and vocal cords being able to synchronize in speech. This set the stage for Homo sapiens to begin communicating on a massive scale. Once in a while, the FOXP2 doesn't get passed. For example, 16 members of a family in England cannot speak intelligibly because they are missing the mutated FOXP2 gene.

Human genes are 98.6 percent the same as our closest relative in the animal world. We do a lot of the same things, and sometimes they do them better such as short terms memory test. The most significant difference boils down to the way we learn as compared to them. Our larger brain facilitates a different learning style. We are susceptible to teaching and once we learn, we remember and will repeat the full sequence of actions even though it may be apparent to us that not all the steps are necessary. On the other hand, our closest relatives will immediately neglect the learned steps and go for the final result. They learn from watching instead of being taught. Our ritualistic style of learning ultimately allows us to do much more complex tasks. In this case, we, like our gene, possess the power of being a replicator. The next most important thing is that we ask: Why? Chimpanzees do not. Additional distinguishing features include a much superior reasoning skill because of our larger brain, an ability to impute intentions to others, and the possession of a genetically based cooperative spirit.

2. Launch of 'Atheists in Foxholes' Book Anthology

Comment #116127 by Steve Crawley on January 25, 2008 at 3:05 pm

Having completed 33 year in the US military, my views about why I risked my life for reasons other than immediate self-defense have matured considerably. Like Ian said in his post, it has a lot to do with the geography of your birth. I think most of you would fight to defend yourself and members of your immediate family. The same reason you would do that also explains why you would also fight for your extended family, your local neighborhood, your village, your city, your state, and yes your country.

We all have reasons to rationalize our actions at each level but for the most part it's the belonging to a place and it's values that constitute us as persons. Believe it or not, we have all been brainwashed since birth to be what we are. I am sure some of us wish we could totally detach and reinvent our self awareness, but then we realize, that's all we have and is worth keeping, even while realizing that it is just a product of our birth and our fighting may not even make a difference.

3. What's the evolutionary advantage of offering your place to an old woman on a bus?

Comment #83251 by Steve Crawley on October 29, 2007 at 12:46 pm

Any of the various kinds of brain images (by products of meme inputs) could have triggered his desire to yield a seat to the elderly lady. The lady could have looked like his mother or possibly reminded him of his grandmother. "Be kind to strangers" or "respect your elders" or any other of the many cooperative refrains persisting from his mimetic environment, could have sparked him into action. Or, it could have been an innate response. I doubt it being the latter because his susceptibility to almost indelible meme inputs is what is innate - not each specific behavior. Humans are much more generalized and complex to process such a simple cause and effect innate response. These are usually reserved for the animal kingdom.

Anyway, behavior is difficult to calculate on a one-to-one basis to determine if the behavior is necessarily advantageous for survival. As environment changes and an individual's activities change from time to time, new and different decision may be in order in similar circumstances. To accommodate for these general eventualities that are definitely going to occur in one's life, evolved behavior is much more generalized to accommodate the vast array of decisions that we make. For efficiency's sake, hereditary behavior often piggybacks on the behavior that evolved for possibly a different reason.

For example, quite a few of our advantageous behaviors such as sex benefit from using the dopamine reward system in the brain. Of course, the possible evolutionary disadvantage of this generous approach is that some non-beneficiary behaviors such as a drug overdose takes advantage of the same reward system. This again demonstrates the competing/conflicting nature of our whole make up. Or, to put it another way, the organism that does the best combinations of cost trades, none of which are perfect, survives.

In any case, whether this specific behavior should be considered advantageous for survival is the question. A human whose ancestors have obviously participated in this behavior before, displayed it. He is still here so it must not be a great disadvantage. Assuming that a non-surviving linage of human might have acted differently in this situation, then within the context of roughly comparing, we can speculate that the behavior of the live human is on the positive side :)