As tales of courage emerge following the mass shooting in a Colorado theatre, one expert says heroes aren't born they're made.

A professor of psychology at the University of Massachusetts says it's not just one human quality that predicts whether a person would save someone.

Ervin Staub tells The National Post that "being a hero" requires a combination of socialization and experience helping others.

He says boys and girls are usually raised to be caring and to think about others and when they have the smarts to act in emergencies,  their actions can be automatic in a moment of crisis.