The Big Question: Why Are We Here?

Some 15 million Americans struggle with depression—an illness that comes in many forms—from major depression and seasonal affective disorder, to dysthymia and <a href="http://www.psychologytoday.com/conditions/bipolar-disorder"

Suicide is a tragic event with strong emotional repurcussions for its survivors and for familiest of its victims. The Center for Disease Control's statistics reveal that more than 35,000 people committed suicide in the U.S. in 2008.

Motivation is literally the desire to do things. It's the difference between waking up before dawn to pound the pavement and lazing around the house all day. It's the crucial element in setting and attaining goals—and research shows you can influence your own levels of motivation and self-control.

Why do we often think we know what we want, only to be disappointed with our purchases and choices? Behavioral economics studies just how irrational we humans can be.