This is hidden brain.
I'm Shankar Vedantam.
There are two kinds of challenges we face.
One kind involves a novel problem.
We don't know why we're sick.
A new disease suddenly sweeps the world, and it doesn't have a cure.
Novel challenges call for discovery, invention.
As a species, we are very good at coming up with such discoveries.
But many of the setbacks in our lives are not caused by such problems.
They are caused by problems whose solutions were discovered a long time ago.
Think about the leading causes of death in most countries.
They're connected to smoking, diet, and sedentary lifestyles.
We know what we ought to do to live better.
We should eat right and exercise, get a good night's rest, live within our means.
Every year, many of us include these sorts of changes in our new year's resolutions.
And every year, most of us fail to follow through for more than a few weeks.
Making a change, it turns out, is hard.
And sustaining it is even harder.
The question is why?
Some of us figure out that we have two selves and that they are in conflict, and this is a challenge we need to resolve.