Effects of generalization descriptions on risk perception.

The study addresses the effects of generalization descriptions on risk perceptions. In a 1-factorial online experiment, 629 participants were randomly allocated to one of three groups. Group G1 received an excerpt of an original press release from the International Agency for Research on Cancer (IARC) regarding mobile phones and cancer, classifying RF EMF as possibly carcinogenic to humans. Group G2 received an additional explanatory text module, and Group G3 received a rewritten text, with both G2 and G3 highlighting that the possible cancer risk only refers to mobile phones. Risk perceptions regarding cell phones and related personal devices, base stations, and high voltage power lines were used as dependent variables measured before and after text reading. Further, the degree to which participants generalized from cell phone-related to other RF EMF exposures was assessed to determine whether this was predictive of their post-text risk perceptions. Regarding risk perceptions, no differences between the three groups were observed after reading the presented texts. Instead, all three experimental groups indicated increased risk perceptions for all electromagnetic field sources. However, we found significant differences according to the prevailing risk generalization belief. Respondents expressing a strong risk generalization belief showed significantly higher risk perceptions for all tested EMF sources (except mobile phones) than subjects with a weak risk generalization belief.

Eliminating the effects of reporting bias on risk perception.

Taking the public discourse on health risks due to aluminum in antiperspirants as an example, we conducted a randomized controlled study with repeated measurements to research how selective reporting of risk information affects risk perception and trust in risk information. First, the study varied the information scope that the experimental subjects received (selective vs. complete information). Selective information highlighted that a health risk is given. Considering the full range of studies, complete information is indicated the opposite. A second variation referred to the facticity of the hazardous agent mentioned in the risk information (a reference to either an actual or fictitious agent). Moreover, the selectively informed subjects received the complete information after the effects of the selective information were measured. Four risk perceptions constructs were chosen as dependent variables, differing on two dimensions (affective vs. cognitive and personal risk vs. risk for others). In addition, subjects´ trust in the given risk information was measured. The study reveals that presenting selective information amplifies risk perceptions. The effect was observed, irrespective of whether the hazardous agent mentioned in the risk information was actual or fictitious. When subjects who first received the selective information obtained the complete information, indicating no elevated risk, risk perceptions decreased. However, the analysis also indicates that corrective information (indicating no risk) is less trusted than selective information that points to health risks. Furthermore, proper toxicological understanding, i.e., taking into account the dose-response relationship, supports the effect of corrective information on risk perceptions.

Effects of selective outcome reporting on risk perception.

The current study aimed to investigate how selective reporting of study results indicating increased health effects will influence its receiver's risk perception. Using the example of the Interphone Study from 2010 on mobile phone usage and cancer, an online experiment was conducted separating respondents into two groups. One group of subjects was informed selectively about a relationship between heavy mobile phone use and an elevated risk of glioma (brain cancer) only. The other group of subjects was informed about the full results of the analyses of glioma risk by cumulative call time, which suggests that other than for the heavy users, there were no statistically significant elevated risks related to mobile phone use. The results showed that selective reporting of risk information increased risk perception when compared to receiving the full information. Additionally, the selectively informed subjects revealed a stronger tendency towards overgeneralization of the 'elevated brain cancer risk' to all mobile phone users, although this did not extend to an overgeneralization to other electromagnetic field sources or differences in the perception of a usage time dependency for possible health risks. These results indicate that reporting of full results is an important factor in effective risk communication.

Framing effects in risk communication messages - Hazard identification vs. risk assessment.

The way in which risk communication messages are framed can influence recipients' risk perceptions. Despite this, there is a limited understanding of how framing is responsible for influencing risk perception. One particularly important element may be whether a risk communication message is framed as a completed 'risk assessment' (specifying a magnitude of risk to the public as a function of the exposure level), or as a 'hazard identification' (a statement regarding whether an environmental agent could in principle cause detrimental health effects in humans, without addressing whether such effects may occur in practice). The current study aimed to investigate for the first time whether framing a risk communication message regarding 'mobile phones and health' as a hazard identification or as a risk assessment affects the reader's risk perception. Using an online survey, participants were separated into three groups and shown either an original press release from the International Agency for Research on Cancer regarding mobile phones and cancer (Group 1), or the press release with additional text modules intended to frame the press release as either a risk assessment (Group 2) or a hazard identification (Group 3). The experimental manipulation was successful in that framing the message as a hazard identification reduced the number of people that believed the press release was a risk assessment, whereas framing it as a risk assessment was not able to increase the number of people who thought that it was a risk assessment. However, no differences in risk perception were found between the groups. In an attempt to ascertain the reason for this lack of framing effect on the radiofrequency electromagnetic fields risk perception measures, it was found that pre-existing interpretations of risk and hazard strongly predicted risk perception, regardless of experimental group. Participants who believed that the International Agency for Research on Cancer conducted a hazard identification perceived lower risks and were less convinced that radiofrequency electromagnetic field exposure from mobile phones increases cancer risks. The results of the study demonstrate the importance of understanding the distinction between a hazard identification and a risk assessment, and suggest that radiofrequency electromagnetic field risk communication needs to develop means for empowering the public to differentiate between hazards and risks.