You are right that brain cells can and will regenerate under certain circumstances. I agree on that part.
Logic might have nothing to do with it. But the brain will generate
new cells and this has been proven
almost a decade ago. 5 years ago scientist managed to prove that the new cells not only mature, but also
become part of the existing neural network. This concept is called Neurogenesis:
Neurogenesis - Wikipedia, the free encyclopedia
Adult neurogenesis is a recent example of a long-held scientific theory being overturned, with the phenomenon only recently being largely accepted by the scientific community.
There is much more to be found about this in the prominent scientific journals (Nature obviously), unfortunately it's not so easy (or allowed) to copy & paste this on a public forum. Which I why I provide you with the following links. The evidence is quite conclusive.
Salk Scientists Demonstrate For The First Time That Newly Born Brain Cells Are Functional In The Adult Brain
New Brain Cells Mature and Function
I never said there weren't limits. Will humans ever be able to run the 100m sprint in under 5 secs? Doubtfully. But as each generation passes, the average IQ of the population increases. (Although there's a lot to say about the classic IQ tests, but let's not go into that for now, because that's a different matter on it's now). I never said IQ mattered a whole lot, I'm just saying you shouldn't see humans as people that a born with fixed abilities, intelligence. If you have anything to substantiate these claims, I'll be happy to read it.
PS: I don't blame you for not being aware of the recent developments. But you shouldn't argue your case unless you have sufficient evidence. As you said yourself, they are largely based on "personal experience" (I wouldn't exactly count that as a scientific criterium). As for "billions of years of evolutionary evidence", I feel to understand what you mean. In fact, evolution serves to demonstrate that humans are not bound to limits. Or else we would all still be making fire with rocks and our bare hands.
As I see it, the main problem with this debate is that people are unwilling to accept the less glamorous alternative because it is far too uncomfortable.
I have read all about Neurogenesis, and the common denominator in all the articles I’ve read, including the articles you have cited is:
“Despite such work, scientists still did not know if these new cells actually worked like any other neuron, or even if they grew and matured like other brain cells.”
And
“Now Fred Gage has proved they do indeed mature and function. His next task is to find out what these new neurons actually do.”
It just seems that you are jumping to the conclusion that they add to intelligence, whereas I am saying it is inconclusive and unlikely. I have said that new brain cells simply may be replacing dead or damaged brain cells so they don’t actually add anything, especially not intelligence. At one time it was thought that brain cells were the only cells that didn’t regenerate.
So just for the record, I will restate my position. I am NOT saying absolutely and conclusively that brain cells don’t regenerate; I am saying that the brain does NOT add new brain cells in response to increased demand for cognitive functions.
I have quoted some online articles in what I have “written” below.
The cell is the structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as living, and is sometimes called the building block of life. Now, if you believe in evolution as I do, you will accept that very early life on earth and the majority of life on earth today is comprised of single celled organisms. Vital functions of an organism occur within cells, and all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells. Each cell is at least somewhat self-contained and self-maintaining: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. Each cell stores its own set of instructions for carrying out each of these activities.
So, would you agree that a cell does NOT require a brain to function and that it does not need to receive instructions from a brain to function? I think you would have to agree. A single celled organism can’t have a brain because there aren’t enough cells. One cell is all it is and it needs to do everything it can with it.
Moving up a few notches on the evolutionary scale you have simple multi celled organisms. Multi celled organism have evolved specialised cells which are cells designed to do a particular job in an organism. An example of this is the hydra which does not have a recognisable brain or true muscles. Nerve nets connect sensory photoreceptors and touch-sensitive nerve cells located in the body wall and tentacles. The stinging cells of a hydra are specialised and react to stimuli. They are not given instructions by a brain.
So, would you agree that organisms can live and evolve and develop specialised tasks without the need for a brain?
Moving up many notches on the evolutionary ladder are very complex organisms that not only contain multi cells that are specialised but they also contain specialised organs made up of specialised cells. An organ is a group of tissues that perform a specific function or group of functions. Biological tissue is a collection of interconnected cells that perform a similar function within an organism. Human organs include the heart, lungs, brain, eye, stomach, spleen, bones, pancreas, kidneys, liver, intestines, skin (the largest human organ), uterus, and bladder. Now, keep that point in mind, cells make up the tissue which makes up the organ and NOT the other way around.
So, back to the debate about increasing intelligence, remembering that cells make the tissue that make the organ, and the brain is an organ. I cannot understand how or by what process a brain, which is nothing more than an organ made up of Neurons which are electrically excitable cells in the nervous system that process and transmit information, can ‘decide’ to make more neurons on demand. Why don’t our eyes make more rods so that we can see better in the dark? Or better still, develop ultra violet or infra red sensitive cells! The eyes are an organ just like the brain.
The reason, as I see it, is simple. Intelligence isn’t necessarily a biological evolutionary advantage, it is simply the result of an excess of neurons. To say that intelligence can be increased is underestimating the power of the human brain as it stands. I remember watching a documentary where scientists created the concept of a brain index. This was basically a number which represented the amount of brain processing capacity required to maintain essential functions to keep an organism alive. A brain index of 1 means that an organism has just enough capacity to keep itself alive and nothing spare. A brain index of 2 means that it has twice as much as it needs and therefore has spare capacity to do other things. They estimated that human beings have a brain index of 7. Why would a brain that has 7 times the processing capacity required need to increase its intelligence further? Surely it would be far more beneficial to us as a species to get rid or a large proportion of the excess capacity and devote it to developing extra cells for fighting diseases instead of writing poetry and developing weapons of mass destruction. Do you now see why I think the notion of increasing intelligence is nothing but fanciful nonsense?
Your claim that average IQ increases with each generation is simply wrong. Biological changes occur slowly over geological time scales (not counting some micro-organisms that undergo rapid evolution). Ideas evolve rapidly but not our intelligence. If you took an average brain from a human who lived 1000 years ago and compared it to the average brain of someone today they would be identical.
Anyway, don’t take my word for it, now that you mention IQ, try this practical test yourself. Take an IQ test now, without any preparation and note your score. Then, buy/read/study all the books you can lay your hands on that show you how to boost your IQ. Go through all the practice questions and tests, noting your IQ score as you go. I will almost guarantee that by the 3rd IQ test your score will have peaked and you will not be able to increase it further. This will be your ‘true’ IQ.
