Current scientific debates, such as on climate change, often involve emotional, hostile, and aggressive rhetorical styles. Those who read or listen to these kinds of scientific arguments have to decide whom they can trust and which information is credible. This study investigates how the language style (neutral vs aggressive) and the professional affiliation (scientist vs lobbyist) of a person arguing in a scientific debate influence his trustworthiness and the credibility of his information. In a 2 X 2 between-subject online experiment, participants watched a scientific debate. The results show that if the person was introduced as a lobbyist, he was perceived as less trustworthy. However, the person's professional affiliation did not affect the credibility of his information. If the person used an aggressive language style, he was perceived as less trustworthy. Furthermore, his information was perceived as less credible, and participants had the impression that they learned less from the scientific debate.

No abstract

Since most of the Internet is not governed by editors, the validity of online information cannot be guaranteed. Therefore, information seekers have to decide whether they should accept knowledge claims they encounter online. This study analyses how information seekers' judgements of a source's credibility, trustworthiness, and instructional quality are affected by the source's professional affiliation and involvement in supporting studies. In a 2 × 2 between-subject online experiment, 143 participants watched an online video lecture in which an expert argued that organic food is superior to conventional food. The conditions varied in the experiment were the expert's professional affiliation and his involvement in the scientific studies that he presented as supporting evidence. Analyses showed that the information about the expert's professional affiliation and study involvement interacted as participants made their judgements about the source: When the expert was a lobbyist who referred to self-conducted studies, rather than a lobbyist who referred to studies conducted by other scientists, he was rated as less trustworthy; his information was rated as less credible; and his instructional qualities were rated as less positive. For scientists, this effect did not occur.

Background To decide whether online health information is reliable, information seekers apply 2 stretegies: first, information seekers can make credibility judgments by using their prior knowledge to evaluate the validity of the encountered health claim. Second, instead of evaluating the health claim itself, information seekers can make trustworthiness judgments by evaluating the character of the information source. In recent years, information givers from various professions have begun to use enthusiastic language to disseminate their information and persuade their audiences. Objective To systematically explore this phenomenon, the goal of this study was to answer the following research questions: (1) does an enthusiastic language style, in comparison with a neutral language style, increase the trustworthiness of a person arguing in an online health forum and the credibility of his or her information? (2) does working for a university, in comparison with working for a lobbying organization, increase the trustworthiness of a person arguing in an online health forum and the credibility of his or her information? (3) does working for a university in combination with using an enthusiastic language style result in especially high trustworthiness and credibility ratings? Methods In a 2x2 between-subject online experiment, 270 participants read a post from an online health forum and subsequently rated the trustworthiness of the forum post author and the credibility of his information. A total of 2 aspects of the forum post varied, namely the professional affiliation of the forum post author (whether the person introduced himself as a scientist or a lobbyist) and his language style (whether he used a neutral language style or an enthusiastic language style). Results When the forum post author used an enthusiastic language style, he was perceived as more manipulative (P<.001), less knowledgeable (P<.001), and his information was perceived as less credible (P<.001). Overall, scientists were perceived as less manipulative (P=.04) than lobbyists. Furthermore, language style and professional affiliation interacted: When the forum post author was a lobbyist, language style did not affect integrity (P=.96) and benevolence (P=.79) ratings. However, when the forum post author was a scientist, enthusiastic language led to lower integrity (P=.002) and benevolence (P<.001) ratings than neutral language. Conclusions The current findings illustrate that health information seekers do not just react to online health information itself. In addition, they are also sensitive to the ways in which health information is presented (“Which langue style is used to communicate health information?”) and who presents it (“Who does the health information source work for?”).

Since the COVID-19 pandemic hit the global community, politicians as well as scientists increasingly turn to Twitter to share urgent health information using various message styles. The results of our 2x2 between-subject experiment show that if a Tweet is written in lower-case letters, participants perceive the information source as more trustworthy. Furthermore, the information is perceived as more credible, and people are more willing to read the health information and share it via social media. Furthermore, scientists are perceived as possessing more expertise than politicians. However, politicians are perceived as possessing more integrity and benevolence than scientists.