The brain processes and organizes information through various systems. One of those systems is the attentional system, which determines the way your brain handles and organizes information – anything your brain pays attention to, in other words.
In the creaky old house that is your brain, the attentional system is one of the pillars holding everything together.
Over thousands of years, evolution developed a more nuanced system that can be neatly summed up in one little sentence: our brain evolved to focus on one thing at a time. This thing was always the most important thing.
Just picture our ancestors, tens of thousands of years ago, on the hunt. They’re hiding in a bush, clutching their spears. It was a matter of life and death for them to be able to set aside any possible distraction and focus every ounce of their attention on the wooly mammoth – or whatever they were hunting. Only the most important things (like an approaching predator) disrupted their thoughts and caught their attention.
Nowadays, we put our attentional system under stress, because our brains aren’t equipped to cope with the flood of new facts and sights that we face everyday. These days, we’re constantly attempting to do many things at once. Driving a car, listening to the radio, thinking about an upcoming business meeting – it’s not unusual that all these things happen simultaneously.
Here’s the key message: The brain can only focus on a limited number of stimuli at a time.
One way we can see how our brain is better at focusing on fewer things is that our brains are more interested in change than constants.
There’s an easy way to show what that means in real life. Just imagine you’re driving, and suddenly, you notice the road is bumpy. The crazy thing is, a few moments before, you weren’t consciously thinking about how flat and smooth the street was! That’s not useful information. It is useful to notice and think about the street if it suddenly feels bumpy. You could be in danger: the road could be treacherous, or you might have popped a tire.
The point is, the brain notices the bumpy road because it’s different and dangerous, and doesn’t notice the harmless flat road because it’s expected and harmless.
Again, your brain focuses on what’s most important.