It’s dated, no doubt, and there is nary a mention of social media (they call the universe of messaging, “voice, electronic signals, or in print”), but this article seems to set the ground for all of the trainings I’ve attended in the last month. Published in 1991 in the Int’l Journal of Mass Emergencies and Disasters, Fitzpatrick and Mileti details the “psychological and social structural processes that result in [perceptions of risk].”
Basically, this is the process for how people hear, decipher, internalize and decide to take action when given a warning message.
I think that the authors don’t focus enough on the idea that repeated messages given over a variety of media assists the verification/confirmation need that most people have in emergency situations. (See Amanda Ripley’s book, The Unthinkable, for more on that.) But that could be that the science understanding the need for verification was still in its infancy, whereas today it is a central part of our social media “revolution.”
Other than that criticism, much of the article holds up and is applicable to today’s emergency risk communicator. This is a highly recommended read (weighing in at only 11 short pages) that can be had for free at http://www.training.fema.gov/EMIWeb/downloads/IJEMS/ARTICLES/MOTIVATING%20PUBLIC%20EVACUATION.pdf .