When we have learned something, there's this thing called belief perseverance. Having learned something, we tend to cling to that belief, even in the face of overwhelming evidence to the contrary.

You'd think people would realize they're bad at multitasking and would quit. But a cognitive illusion sets in, fueled in part by a dopamine-adrenaline feedback loop, in which multitaskers think they are doing great.

In order to be a world-class expert in anything, be it audiology, drama, music, art, gymnastics, whatever, one needs to have a minimum of 10,000 hours of practice. Unfortunately, it doesn't mean that if you put in 10,000 hours that you will become an expert, but there aren't any cases where someone has achieved world-class mastery without it! So the time spent at the activity is indeed the most important and influential factor.

Most of what we know we don't really know first hand. I've never seen a cancer cell. But I trust this community of experts who have, so I believe that cancer exists. But we trust these experts, and we trust that the experts have a system of checks and balances and self-correction. And we have to insist that experts have certain certifications. They're not perfect. Every once in awhile there's an engine falls off the wing of a plane, or a tax audit happens and you find out your expert made a mistake. But it's a pretty good system. It's the best system we've got.

The brain has an attentional mode called the "mind wandering mode" that was only recently identified. This is when thoughts move seamlessly from one to another, often to unrelated thoughts, without you controlling where they go. This brain state acts as a neural reset button, allowing us to come back to our work with a refreshed perspective. Different people find they enter this mode in different ways: reading, a walk in nature, looking at art, meditating, and napping. A 15-minute nap can produce the equivalent of a 10-point boost in IQ.

Whenever humans come together for any reason, music is there: weddings, funerals, graduation from college, men marching off to war, stadium sporting events, a night on the town, prayer, a romantic dinner, mothers rocking their infants to sleep ... music is a part of the fabric of everyday life.

The Roman philosopher Seneca the Younger (tutor to Nero) complained that his peers were wasting time and money accumulating too many books, admonishing that "the abundance of books is a distraction." Instead, Seneca recommended focusing on a limited number of good books, to be read thoroughly and repeatedly.