Read D, Morgan M G
Center for Decision Research, Leeds University Business School, U.K.
Risk Anal. 1998 Oct;18(5):603-10. doi: 10.1023/b:rian.0000005934.44033.5e.
The AC electric and magnetic fields associated with high voltage power lines have become a concern as a possible health risk. In most cases the strength of these fields decreases as the inverse square of the distance from the line. In earlier work, we found that laypeople do not understand how rapidly field strength decreases with distance. Most believe that any high voltage power line they can see is exposing them to strong fields. This paper confirms the earlier finding and explores a number of strategies which might be used in risk communications to correct this misperception. We found it relatively easy to provide subjects with a better understanding of the range-dependency of magnetic field strength. Moreover, the quality of this acquisition was apparently independent of the manner in which they were instructed. Such successful instruction is markedly different from the well-established difficulty of teaching people about many qualitative domains, such as physics or ideas in probability. Clearly, while some erroneous beliefs are highly resistant to change, others can be altered quite readily. We suspect that an important distinction between knowledge about the range-dependency of power-frequency magnetic fields and less tractable topics involves the presence or absence of prior folk-theories or "mental models" of the domain.
与高压电力线相关的交变电场和磁场已成为人们关注的一个可能的健康风险问题。在大多数情况下，这些场的强度随与线路距离的平方反比而减小。在早期的研究中，我们发现外行人并不理解场强随距离下降的速度有多快。大多数人认为他们能看到的任何高压电力线都在让他们暴露于强场中。本文证实了早期的研究发现，并探讨了一些可用于风险沟通以纠正这种误解的策略。我们发现相对容易让受试者更好地理解磁场强度的距离依赖性。此外，这种认知的质量显然与指导他们的方式无关。这种成功的指导与在教授人们许多定性领域（如物理或概率概念）时所面临的公认困难明显不同。显然，虽然一些错误观念极难改变，但其他一些观念却很容易改变。我们怀疑，关于工频磁场距离依赖性的知识与较难处理的主题之间的一个重要区别在于该领域是否存在先前的民间理论或“心理模型”。
