At the beginning of the year, many of us make resolutions for the months to come. We vow to work out more, procrastinate less, or save more money.

Though some people stick with these aspirations, many of us fall short. How do we actually develop good habits and maintain them? What about breaking bad ones?

Wendy Wood, a psychology professor at the University of Southern California, has some insight on this. She’s been trying to understand how habits work for the past 30 years. According to Wendy, habits are mental associations.

Full story at NPR