One of the things that make it easy to concentrate is novelty. To a baby, his toes are a novelty - what are they? what do they do? why are they there? - and babies can be transfixed for hours, or until the next novelty comes along. Certainly, the novelty of our toes wears off sooner or later.
The older we get, the more used we are to what happens in life, and the less novel it is. The first time you take a bus as a child, it’s an exciting event. The more times you do it, the less interesting it becomes until, over time, it’s just a routine backdrop to your life and you hardly register it.
So, day-to-day events hardly warrant the sort of attention we originally gave them. We can do a whole sequence of things with hardly a thought. Then we leave one room to collect something from another, and realise we’ve forgotten what we came for. Help! Is our memory deteriorating?
Sure, the most notable psychological feature as we age is short-term memory impairment and lengthening of response time, so we take a little longer to retrieve and process information. But remove the differences that these two factors contribute to tests based on vocabulary, general information and well-practised tasks, and results show negligible differences between older and younger adults.
What’s more likely is that you've got out of the habit of concentrating on what you were about to do – because most of the time with routine tasks you don’t have to.
So, time to get back into the habit of concentrating. Time to stop multitasking and asking your brain to juggle six things at once. Time to concentrate.