However, when asked about the overall risks that these hazards pose to their well-being, people's judgements extend far beyond the statistical chances of dying. We find risks more acceptable if we can choose whether or not to take them, if we can control our level of exposure and if the benefits are clear and immediate. Mobile phones are an obvious example. Despite the sensational media stories, most people have carried on using them. On the other hand, we object to hazards that are imposed on us without our consent, that affect the young or could cause a major catastrophe, or when risks and benefits are inequitably distributed across society.
Nuclear energy is one example.
Often, controversies about risk seem to be more about politics and ethics than about the science. This, I suspect, is the case with the mapping of the human genome. The mathematical approach may indeed be counterproductive, particularly with long-term hazards such as radioactive waste disposal, where it is very difficult to predict accurately what the future risks might be. But the most crucial factor that dictates how people judge risk is trust. Many experts claim that a mistrust of expertise and risk management is now a defining feature of industrialised societies.