Excellent article on recent research around attention, daydreaming and our brain's "default mode".

The human brain evolved to focus on one thing at a time. This enabled our ancestors to hunt animals, to create and fashion tools, and to protect their clan from predators or invading neighbors. In parallel, an attentional filter evolved to help us to stay on task, letting through only information that was important enough to deserve disrupting our train of thought. This filter is what captures your attention when you hear someone mention your name in a crowded room even if you aren’t aware of what they were saying a moment earlier — the system is monitoring events at a pre-conscious level in order to promote some events to consciousness and ignore others. This attentional system is one of the crowning achievements of the human brain, and the focus it enables allowed us to harness fire, build the pyramids, discover penicillin and decode the entire human genome.

But a funny thing happened on the way to the twenty-first century: The plethora of information and the technologies that serve our brain changed the way we use it. 

To read more visit:  https://medium.com/book-excerpts/daydreaming-is-the-brains-default-mode-b82007db652f