Ebtx is losing his mind
I've noticed that after 49 (which is supposedly your best year as far as being a good driver is concerned), I am less and less able to hold my lane while shifting my attention to other things on the side of the road. I used to be able to look all over the place and my "auto-pilot" worked just fine. Not any more. Now, I have to consciously look where I'm going all the time and if I have to look at something elsewhere, I have to do it quickly. It's not like I'm going to get into a headon soon ... it's just a minor irritation.
I also find I'm more distracted by my grandkids in the back seat screaming and so forth.
When I take a piece of mail to put in the box by the Quick-Mart on the way to work, I forget to stop there. I have tried various methods to remember. For instance, I don't turn on the radio until I send the mail. Or ... I hold it in my hand while I drive. All methods I try fail eventually. The cause is that I am thinking of other things and ...
The Secondary Focus of Attention fails.
"You" is the primary focus of attention. There are many focuses of attention going on in your mind. There is a hierarchy of separate "people" within your brain. Something like multiple personalities. Take the case of a "split-brain" patient. Here, the corpus callosum is cut to prevent seizures. The result is two different people in the same body. They coexist easily and the two are still capable of walking, talking and chewing gum at the same time. But subtle tests can detect their separate existence. "You" are many people. Your sense of individuality is formed by the fact that only one of these "persons" takes the primary focus and all of them are extremely attuned to one another ... like Siamese twins ... they have to get along. And they all exchange pieces of one another on the fly.
Anyway ... when you get old, that hierarchy of extra helpers collapses and you end up with just the primary focus. Nobody is monitoring the road when you look to the side for very long.
Can you see why people would be "set in their ways" when they get old? They can only concentrate on one thing at a time ... so ... they get rid of extraneous other "ways" so as not to be distracted. They can't cope with multiple, simultaneous options any longer.
I would like to think that this is caused by brain cell deterioration
If so, it is like your body falling apart gradually. However, this may not be true in the case of our brains. It is possible that they are simply "saturated" by information and the result is dysfunction. What if nature has given us a brain capable of storing information to an expected age of say, 30? If we run out of space what happens? What form would overload take?
Well, I would expect old and unimportant information which is not reinforced by "remembering" would be sacrificed in favor of new info which is of immediate use. Your memories of childhood should fail. In fact, they do. I remember things from my childhood ...but ... I can no longer put myself into that memory as though it "just happened yesterday". This means that all the background information connected to that memory has been lost or more likely overwritten. Now. you are left with just a worded synopsis of the event. You feel like it could be something you read in a book.
Short term memory is failing also. Apparently, it is being crowded out. This type of memory is just a temporary storage area to put stuff in ... to avoid feedback problems ... then it's integrated into permanent memory while we sleep (dream). If we needed more storage, it's conceivable that this space might be taken over leaving us "absent-minded".
Note also that the quality of the information in our brains is irrelevant. It takes the same amount of bytes to store "Gone With The Wind" as ten (or twenty?) porn paperbacks totalling the same length. The amount of information we store is generally proportional to the time we have lived (provided you didn't live in a dark room all the time).
If all the foregoing is true ... we may need to modify our genetic structure to accommodate an extended lifespan which is potentially a bigger problem than Alsheimers. Imagine being able to live to the ripe old age of 250 but not being able to find your way back to your car in the mall parking lot ...