dont worry about losing to a computer or a player using one to cheat. the only person it hurts is the player using computers to find moves since it negates any learning they might have gained from the game. You get to play a stronger opponent win or lose. Sooner or later they get caught and removed...
as a note ash computers people are using beat us normal humans (there are some specialist IM/GM that force them to work) everytime...
I think this is a developmental issue and would be an interesting study.
Better get sapientdust started on it right away.
Borgqueen has it sorta right that new connections are made based on experience but this is more difficult as we get older.
Hey BQ, turns out you're sorta right. Pretty cool, huh? 
Sorta cool.
Usually when I have this rant, it's on the topic of language (that's my academic background), and the popular myth of language learning being easier the younger you are, when in fact the inverse is true.
Really? I know that I have bought into that particular popular myth hook, line, and sinker, but I would very much like it not to be true. I know that in my personal experience, my attempts to learn language after age 40 have been very much unsuccessful, at least compared to the same amount of effort back when I was aged 15-20, the last time I made a serious effort, in high school and college.
Do you have any research to support that position? As I say, I would love it if you were correct.
Ask sapientdust.
Yessirree, research would certainly beat our mere personal experience any day... 
Research is fine -- but the results are likely to be amended by future research. Use your own introspection ability. For example I'm aware that with every passing year my vocabulary increases. So this is surely going to apply to everyone. I remember reading a particular book (Charles Chaplin's biography actually) in my early twenties. Every page contained at least one word I did not know the meaning of and I was annoyed by Charlie for using such "difficult" words. But, notwithstanding that the book was excellent. However, I read the book again when I was about 40, expecting to find the same problem and kept a dictionary near. But -- behold! I didn't need the dictionary at all then and I found few,if any, words I needed to look up. Now that I'm much older I just know my vocabulary increases somewhat every year. So there's one good thing about growing older! By the way, I'm sure chess prowesss improves with age also -- providing good health is maintained. Lightning chess should be avoided, simply because it raises stress levels. But that applies for all ages.
"I know someone who learned Spanish when he was 50" just isn't very convincing. There really is a lot of academic research on the relationships between age and the ability to learn a language. Most of it is focused on young children, pre and post puberty, but I know that language acquisition in middle age and beyond has also been the focus of reasearch. If that was indeed David Styles' academic specialty, I'm sure he's familiar with it. (Although it isn't completely clear whether his academic background in language was as a student, teacher, or researcher.)
At any rate, both reading and experience have predisposed me to believe that language acquisition becomes much more difficult above 40. This is one case, though, where I would sincerely love to be wrong.
As for Chess, it seems to me that Chess learning also becomes more difficult later in life, but once again,I would love to be shown to be wrong. I don't have nearly the level of interest in Chess that I do in language, but it would be nice to know that if I ever did decide to put in the effort to improve significanty at Chess, it would not necessarily be wasted.
Yes there is research that supports learning at various ages. Its just a fact that we can learn faster at younger ages and much slower as we get older. it doesnt mean its impossible to learn something when we are older just more difficult. you can easily do some quick searches and find VALID reseach online. careful of online garbage though that isnt peer reviewed.
adding vocabulary is a minor modification to memory not a large addition. even a few 100 words is nothing in language. The hard part in language is learning of rules. Something that native speakers do automatically and intuitively for the most part (and yes make errors in as well). Once the formation of the infrastructure is formed adding words to it is a small task. Language btw, is the most difficult thing we ever learn. We start at birth and spend the rest of our lives trying to master it. (a lot like chess huh?)
YOU ARE NEVER TOO OLD TO PLAY
I'll tell you this, it's an individual thing.
I live in a retirement community. Very few chess players here. Most play card games (simple ones), dominoes...
What I've found is that most people have never been deep thinkers. They believe what everybody believes. They do what everybody does. They wear the same style clothes that everybody wears. They make decisions by consensus.
To play chess...to think deeply...to think independently and freely...they can't and never could do this.
That's how most people are. Just commenting; not judging. But...I am glad that I am me and not like them.
An interesting story. Back in the 80s when I first started to play against serious players I asked a local master if Reshvesky, who was in his 80s at that time, was any good still since he was about 2300 at the time but no where near the strength he was at his prime. The 2300 master told me well he makes more tactical/calculation mistakes in complex positions than he used to but if you play something he "knows" then he is very very strong. ie dont play classical systems with a plan he knows cold or a clear endgame against him.
If someone is out of their teen-age years and they start a completely new activity, they have no reason to expect that they'll ever be "good" at it compared to people who have been doing it all their lives. If you are older and just start playing piano, then you shouldn't expect to be a concert pianist playing with a professional orchestra. If you are older and just start learning languages for the first time, you shouldn't expect to become fluent in multiple languages without any accent. If you're older and you just start learning to play tennis or golf, then you shouldn't expect to play on the pro tour.
Likewise with chess. As you get older, the way we learn changes because of physisiological changes in our brain. Our recall of material we learn in our later years is lower than when our brain was still rapidly forming new neural connections. That's just reality.
Now, that doesn't mean one can't improve some specific area of one's game as you age. But any expectations that one will become a master if one didn't learn the game young and spend lots of time developing the basic skills early in life need to be shelved. Just play to enjoy the game, work as hard as is enjoyable, and get as good as you can get.
Now all that said -- I'm in my 40s, I've hired a coach, and he assures me that while I won't ever be an IM, the skills needed to reach about 2000 to 2200 are within the reach of most people regardless of age. Getting to 1600 is just pretty much about developing the discipline to not drop pieces and pawns to simple tactics, and another 400 points or so can be had by experience, learning to calculate and visualize better, and learning some basic planning and strategic ideas. (or so he assures me).
Yes, it'll take several years of hard work. But it's (suppossedly) that much is doable :)
Yes, it is doable.
And I have to laugh that you are only in your forties and are feeling "old". I know...I know...I've been there. And I have three children in their forties who are feeling "old".
I'm still working on improving. My goal is 1800...I'm getting there. I probably could hit 2000...but I don't know that I want to put in the additional work. There are, after all, other priorities that I have.
Yes, it is doable.
And I have to laugh that you are only in your forties and are feeling "old". I know...I know...I've been there. And I have three children in their forties who are feeling "old".
I'm still working on improving. My goal is 1800...I'm getting there. I probably could hit 2000...but I don't know that I want to put in the additional work. There are, after all, other priorities that I have.
Compared to my Grandmother, I'm young. But when it comes to neurology, I'm "old" in the sense that what my neurons are doing now is not what they were doing when I was young. And no amount of telling myself I'm only as young as I feel will change that :)
No, I realize all that. That's why my golf is going downhill, as well (mostly just distance at the T-box...I chip, pitch and putt better than ever!).
BUT...I'm still within my potential at chess.
And, so are you. You even said so. 
http://www.wired.com/techbiz/media/news/2002/02/50724 Good article on it. Get exercise too.
Let them use computers if they want to. I beat Chess Titans at the 10th level about 50% of the time,so I wouldn't worry about that and it's because of the odd blunder that I lose anyway. Computer chess never blunder but they have limited imagination.