When you get older your mental capacity shuts down. I recently read an article saying that your StarCraft 2 ability goes down at the age of 24. It makes sense because there is a lot going on when it comes to a StarCraft 2 game.
It also makes sense that when you get older you are not mentally as sharp. It's harder to learn new things as you get older. Even simple things can be harder than it sounds. I recently played a game to teach kids math. In this game 1-5 animals went into a barn and 1-5 animals left. You had to pick how many animals and what kind of animals remained in the barn. This sounds really simple right? For me I got it right but it was doing the task was much harder than I anticipated.
I have also noticed that older people who are into technology are more "with it". This leads me to believe if somebody is using the most current technology for some reason they are more cognitively able.
When you start to think about it it makes perfect sense. Technology changes all of the time and you have to find a new way of using it. When I upgraded from iOS6 to iOS7 there were a few things that I found hard to do. By using this technology I learnt how to do something new. When you use technology more this happens all of the time.
The short answer is that people are learning when they are simply using technology.