## 1 Background  
### Introduction  
Over the years, the services offered by wireless networks have modified our daily life. At first quickly adopted for their portability, mobile phones have become an indispensable tool in daily life. Wireless networks have increased enormously in recent years, and this trend is expected to continue [1]. Nowadays, base stations, smartphones, tablets, and WiFi routers are found nearly everywhere. The electromagnetic fields (EMFs) emitted by their antennas depend on the power emitted, and their amplitudes are inversely proportional to the distance of the antennas (the sources). However, such radio frequency electromagnetic fields (RF EMFs) also depend on the directivity and gain of the antennas that are focusing the signal toward areas of interest. Therefore, RF EMF human exposure is difficult to assess intuitively. Although the distance to the antenna can be estimated visually, the power emitted, the directivity and the frequency are not perceptible by human senses. It is, therefore, not scientific facts, such as RF EMF exposure levels [2; 3], but rather, intuitive beliefs are crucial to a non-expert's risk perception, as eloquently expressed by [PERSON] years ago: _\"The risks that kill you are not necessarily the risks that anger and frighten you\"_[4]. Consequently, exploring the construct of intuitive risk perception has been a research focus for many years. From a utilitarian view, both perceived risks and perceived benefits determine the preferences for options [5]) in general and, in particular, the acceptance of technologies [6]. However, because risk issues play a dominant role in public debates about modern technologies--such as wireless communication--social science research has focused on risk perceptions. Despite, or perhaps because of, the large number of studies conducted in this area, definitions of risk perception vary to a considerable degree. A look at the questionnaire items with which risk perception is assessed reveals the broadness of what is conceptualized as risk perception. Some use \"worry\" or \"concern\" interchangeably with risk perception, or see both as a single dimension of risk perception (see feelings-of-risk, [7; 8]), while others have argued for a separation of these concepts [9]. Some measures could be termed as cognitive, while others involve stronger emotional cues. There have also been attempts to combine affective and cognitive items in the same scale (e.g., [8; 10]). In the current study, we focus on something that--in our view--most questionnaire-based risk perception studies have in common, i.e., that researchers measure risk perception with one or more rather abstract, closed questions. For instance, in the Eurobarometer study from 2010 [11], participants were asked _\"How concerned are you about the potential health risks of electromagnetic fields?\"_ on a 4-point Likert scale ranging from _\"not at all concerned\"_ to _\"very concerned\"_. According to this assessment, 46% of European citizens are _\"fairly\"_ or _\"very concerned\"_ about the potential health risks of electromagnetic fields (EMFs), while 51% are _\"not very concerned\"_ or _\"not at all concerned\"_. However, this approach can be criticized both on the grounds of survey methodology in general (see [12] for a review) and risk perception measurement specifically [13; 14]. Comparing closed question measurements of risk perception with qualitative data, [PERSON] [13] and [PERSON] [14] both argue that Likert-scale measurements overestimate the \"true\" level of perceived risk. According to [13], this is especially a problem with technical and environmental risks. As a remedy, he suggests measuring the subjective importance of a variety of risks at the beginning of a risk perception questionnaire, so that a comparative evaluation of technological, social, environmental and everyday life hazards, becomes possible. The same problem has also been identified regarding the \"worry\" of becoming the victim of a crime [15].