We've all seen pictures of Hurricane Katrina survivors waiting on rooftops and rowing through the flooded streets of New Orleans. These striking images raise the question, "Why did these residents stay behind?"

For more insight into the quirks of human nature, visit Were Only Human at psychologicalscience.org/onlyhuman. Were Only Human is written by Wray Herbert and brought to you by the Association for Psychological Science.

Song Credit: "Stormy Weather" by Rosemary Clooney