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This may be a stereotype, but many of us encounter a lot of people who insist that they can't learn a new technology because they're too old. Some of these people can be brilliant learners in their youth - doctors, lawyers, prominent businessmen, academics. It's so common that one benchmark of good web design is whether the 'average grandma' can use it.

A part of this might be from the formation of habits - someone who's used to reading the newspaper for 50 years would have trouble replacing that with online news. Another possibility is that they may feel that they have limited years to live and don't want to spend their limited time learning a new skill, or that they would have a poor ROI on these skills.

But do they actually have more difficulty learning from a physical perspective or is it just psychological?

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2 Answers 2

up vote 4 down vote accepted

Firstly, the matter of lifestyle is probably a significant factor. Someone who is an alcoholic their whole life and never tries or learns new things is going to have a different outcome that somebody who is still learning new things and exercising and eating healthy.

That being said, lifestyles equal, there's at least two factors in age-associated reduction in memory and learning. Firstly, just like hips and shoulders start falling apart, so does the brain (characterized by morphological abnormalities and synapse loss). Organisms are very complex machines and lots of the equipment is gradually failing throughout our life. Dementia is a typical result of age-induced wear and tear on the brain.

The other is reduced plasticity. We start off with a very plastic brain, which allows us to learn our environment. However, part of the process of learning is to stabilize our learning circuits so that they can't be changed again (i.e. you want memories to stay as robust as possible). Our whole brain goes through series of this stabilization. At 4-5 years, pruning removes "unused circuitry", greatly reducing plasticity. In the early 20's, our frontal lobes finalize and myelinate (and this is thought by some to pertain to why people start practicing better judgment at this point).

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There are recent personality theories that assume that personality traits are stable only because we keep our environments stable. We create our lives in a way that continuous change is not necessary. I wonder if something similar can be said about learning: we create our lives in a way that continuous learning is unnecessary, thereby reducing our ability to learn (because we have no practice and forgot how to learn, or because our "brain muscle" is untrained, or quite simply because we don't want to learn, now that we feel we know enough). –  what Apr 7 at 7:18
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I'm sure environment plays a significant role, but the biological role is well documented. –  Keegan Keplinger Apr 8 at 23:43
    
I'm no expert in this, but I always had the impression that no researcher ever thought of comparing differnt kinds of old people: those that led lives that forced them to continually keep learning at the same rate as adolescents do (learning new languages, new skills, new social conventions etc., e.g. diplomats moving to new countries every few years) with those that learn a job and stick with it until retirement. Research has shown that training can make good about 10 IQ points. That's about what old people loose, compared to young! –  what Apr 9 at 4:48
    
Hmm, SE keeps deleting @KeeganKeplinger from my comments. Why is that? (It stays here because I put it in backticks.) –  what Apr 9 at 4:49
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Who do you think it is underestimated by? Society in general or researchers? I would argue that most people studying behavior account for it. The general method for teasing environmental from genetic traits is monozygotic twin studies. Here is one such study, Here is another, and Here is a review on the "use it or lose it" perspective. –  Keegan Keplinger Apr 9 at 11:58

It's better that way

Disregarding how this is implemented biologically, the answer to why is because it provides optimal results.

In learning systems where you are able to freely adjust the ability to learn - e.g., AI research 'reinforcement learning' paradigm, there is a tradeoff commonly called Exploration vs Exploitation - i.e., should the agent focus on gaining new experiences by trying out new solutions that might be worse or better (but you don't know), or should it do things in the way that it believes to be best, and ignore the other options. Quite intuitively, you do get the best results by focusing on exploration early-on when you have little knowledge, and avoiding exploration after you have 'sufficient' amount of experience.

Similarly, in learning systems which "passively" receive new knowledge, there is a balance decision - how much should you alter your beliefs after seeing new evidence. If a two year old kid saw a flying man, it'd make sense to believe that men could fly - after all, two year olds see radically new phenomena almost every day, and it is useful to adjust their beliefs to note "ok, X is working that way, and Y always happens before Z" - even if they'd just seen it a single time. However, if a sixty year old saw a flying man, it'd instead make sense to look for wires and a movie camera crew. Similarly, in machine learning systems it is optimal to slow down belief adjustment(=learning) with time - as you've accumulated a larger baggage of earlier evidence, the newer evidence is comparatively much less important.

Now, going back to people - as per the above examples, in any learning system, you get the best results by slowing down your learning rate with time. Learning is a very useful capability for survival&reproduction; doing learning properly is a competitive advantage in natural selection.

So there is evolutionary pressure to do it this way - it should be expected that all animals, including us, would have evolved some biological way to adjust their learning so that it slows down with age. Animals would experiment and learn during adolescence, and afterwards mostly stick to the already formed habits. Changing neuronal plasticity is one way to implement this, there may be others.

Of course, it may be that it's no longer optimal given the radical change in our lifespan - if you live twice longer, then it'd be useful to learn twice longer as well - but it's originally implemented because it is (was?) actually an advantage to have it that way.

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