Fear-based appeals appear to be effective at influencing attitudes and behaviors, especially among women, according to a comprehensive review of over 50 years of research on the topic, published by the American Psychological Association.

"These appeals are effective at changing attitudes, intentions and behaviors. There are very few circumstances under which they are not effective and there are no identifiable circumstances under which they backfire and lead to undesirable outcomes," said Dolores Albarracin, PhD, professor of psychology at the University of Illinois at Urbana-Champaign and an author of the study, published in the journal Psychological Bulletin.

Fear appeals are persuasive messages that emphasize the potential danger and harm that will befall individuals if they do not adopt the messages' recommendations. While these types of messages are commonly used in political, public health and commercial advertising campaigns (e.g., smoking will kill you, Candidate A will destroy the economy), their use is controversial as academics continue to debate their effectiveness.

To help settle the debate, Albarracin and her colleagues conducted what they believe to be the most comprehensive meta-analysis to date. They looked at 127 research articles representing 248 independent samples and over 27,000 individuals from experiments conducted between 1962 and 2014.

They found fear appeals to be effective, especially when they contained recommendations for one-time only (versus repeated) behaviors and if the targeted audience included a larger percentage of women. They also confirmed prior findings that fear appeals are effective when they describe how to avoid the threat (e.g., get the vaccine, use a condom).

More important, said Albarracin, there was no evidence in the meta-analysis that fear appeals backfired to produce a worse outcome relative to a control group.

"Fear produces a significant though small amount of change across the board. Presenting a fear appeal more than doubles the probability of change relative to not presenting anything or presenting a low-fear appeal," said Albarracin. "However, fear appeals should not be seen as a panacea because the effect is still small. Still, there is no data indicating that audiences will be worse off from receiving fear appeals in any condition."

She noted that the studies analyzed did not necessarily compare people who were afraid to people who were unafraid, but instead compared groups that were exposed to more or less fear-inducing content. Albarracin also recommended against using only fear-based appeals.

"More elaborate strategies, such as training people on the skills they will need to succeed in changing behavior, will likely be more effective in most contexts. It is very important not to lose sight of this," she said.