In a second experiment, Slovic and Alhakami had students of the University of Oregon rate the risks and benefits of a technology (different trials used nuclear power, natural gas, and food preservatives). Then they were asked to read a few paragraphs describing some of the benefits of the technology. Finally, they were asked again to rate the risks and benefits of the technology. Not surprisingly, the positive information they read raised – student’s ratings of the technology’s benefits in about one-half of the cases. But most of those who raised their estimate of the technology’s benefits also lowered their estimate of the risk – even though they had not read a word about the risk. Later trials in which only risks were discussed had the same effect but in reverse: People who raised their estimate of the technology’s risks in response to the information about risk also lowered their estimate of its benefit.
Excerpt from: Risk: The Science and Politics of Fear by Dan Gardner