Improving lay understanding on high voltage power lines: Predictors of the perception of risks and exposure

Does the presentation format matter? Effects on lay understanding of electromagnetic fields originating from high-voltage power lines

Every citizen is exposed to low frequency electric and magnetic fields in everyday life which emanate e. g. from vacuum cleaners, smartphones and high-voltage power lines (HVPL). Low frequency fields are not visible to the human eye. In order to be able to assess the strength of these fields and thus the level of exposure, citizens as laypersons are dependent on experts’ display of measurement results. Yet, there is apparently no consensus in research on the question of how respectively in what presentation format field strength of electromagnetic fields (EMF) can ‘best’ be communicated to laypeople (Nielsen et al., 2010; Timmermans et al., 2008; Slovic et al., 2005; Ancker et al., 2006), although there are first hints that different presentation formats might affect the perception and understanding of the information (Claasen et al., 2017; Morgan et al., 1985; Wiedemann et al., 2018). In particular, there is a lack of experimental study designs that analyze actual cause-effect relationships. This is where our study starts.
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The aim of this paper is to examine the effects of different ways to visualize and communicate the measurement results of EMF originating from HVPL. Our focus is on the effects of different presentation formats. We address the overall research question: Does the presentation format affect the understandability of the provided information and/or recipients’ risk, exposure and/or safety perception of of low frequency magnetic fields?
We conducted an experimental study (N=274, 1x3-between-subject-design) combining a standardized representative survey of the German population with three experimental groups for three self-developed presentation formats (video, information graphic, diagram). Within the survey we demonstrated how an expert measures the exposure of a HVPL and compared his result with e. g. the legal maximum permissible value of exposure or the strength of the magnetic field in combination with an operating vacuum cleaner.
The experimental study shows (1) that the presentation format influences recipients’ risk perception: after watching the video or looking at the information graphic research participants’ risk perception was significantly reduced compared to the risk perception before watching the video or the information graphic, whereas this is not true for the presentation format ‘diagram’. However, (2) the presentation format has neither had a significant impact on recipients’ exposure and safety perception nor on the perceived understandability of the provided information. The recipients felt equally well informed by all presentation variants. An interesting secondary finding is that using comparisons to e. g. regulatory values are useful to inform citizens in an understandable manner about the exposure of EMF from HVPLs.