I happened to have recently picked back up Kahneman's book Thinking Fast and Slow, and he summarizes some interesting research on these topics. First on page 138 after showing results from Slovic's research that people were really bad a judging the relative risks of dying from different cases, Kahneman concludes:
The lesson is clear: estimates of causes of death are warped by media coverage. The coverage is itself biased toward novelty and poignancy. The media do not just shape what the public is interested in but are also shaped by it . . . Unusual events (such as botulism) attract disproportionate attention and are consequently perceived as less unusual than they really are. The world in our heads is not a precise replica of reality; our expectations about the frequency of events are distorted by the prevalence and emotional intensity of the messages to which we are exposed.
That last sentence is revealing: the key to creating a public panic is to 1) make the issue emotional and 2) repeat the message so that it is readily available in people's memory. A few pages later (p. 142), he develops this idea further when discussing Sunstein's research:
An availability cascade is a self-sustaining chain of events, which may start from media reports of a relatively minor event and lead up to public panic and large-scale government action. On some occasions, a media story about a risk catches the attention of a segment of the public,k which becomes aroused and worried. This emotional reaction becomes a story in itself, prompting additional coverage . . . The cycle is sometimes sped along deliberately by 'availability entrepreneurs,' individuals or organizations who work to ensure a continuous flow of worrying news. The danger is increasingly exaggerated as the media compete for attention-grabbing headlines. Scientists and others who try to dampen the increasing fear and revulsion attract little attention, most of it hostile: anyone who claims that the danger is overstated is suspected of association with a 'heinous cover-up.' The issue becomes politically important because it is on everyone's mind, and the response of the political system is guided by the intensity of public sentiment. The availability cascade has now reset priorities. Other risks, and other ways that resources could be applied for the public good, all have faded into the background.
Beware of the availability entrepreneur.