Kenneth Vail at the University of Missouri reviewed experiments involving people thinking about death. He also reviewed assessments of how people who were not directly involved in catastrophes responded after learning about them.
Vail said people commonly felt a need to reach out to others, and often did reach out.
"Seeking comfort from loved ones, and striving to uphold important values that help restore the perception that the world is a predictable and benevolent place," Vail said in a statement. "This includes wanting to be tolerant and compassionate."
The study was published in the journal Personality and Social Psychology Review.