A German study published in June in the Journal of Language and Social Psychology suggests that readers may actually be skeptical of science blog article statements that are presented as overly certain.

While some degree of uncertainty can be seen as a characteristic of every form of empirical results (Popper, 1968), this is particularly true in the case of current scientific debates, for example, on the effects of new technologies (“What are the risks and benefits of stem cell research?” “Should genetically modified food be banned?” or “Are computer games dangerous for teenagers?”). In these contentious fields, studies frequently present patterns of conflicting evidence which do not lead to straightforward conclusions on the “correct” view. – Winter et al. 2015

Science communicators have often been hesitant to incorporate scientific uncertainty into popular accounts of scientific research. For starters, previous research has shown that powerful language, including scientific statements presented as certain and assertive, is more influential and credible. Scientists have also worried that lay readers will misinterpret statements of scientific uncertainty and thus mistrust science or delay action on pressing issues such as climate change. As science communicators, we often figure that wishy-washy language on scientific findings won't captivate our audiences like powerful metaphors and conclusive statements will.

Scientists could focus on the knowns before the unknowns. Communicators could re-frame the issue as one of risk, a concept familiar from the insurance industry, rather than uncertainty. -The communication of uncertainty is hindering climate change action, The Guardian

It has been assumed that the general public is unable to conceptualize information about risk uncertainties, and so communication about food risk has tended to avoid this type of information. - Public preferences for informed choice under conditions of risk uncertainty

In a new study, Stephan Winter, Nicole Krämer, Leonie Rösner and German Neubaum investigate how lay readers deal with scientific uncertainty in popular online science texts. The researchers conducted an experiment in which they had participants read different versions of a blog post about the effects of violent computer games on children. The different versions of the blog post contained different language styles and elements of certainty or uncertainty.

The main purpose of the study was to find out if powerful scientific statements are perceived as more credible and persuasive, or on the other hand if more hedged scientific statements (e.g., “The study may indicate that playing violent video games could lead to a higher level of aggression”) are actually more credible in news coverage of science.

Within online science articles, scientific uncertainty can be expressed through linguistic elements within the description of certain pieces of evidence (e.g., in a summary of results of an empirical study). This may arise through words like “might,” “could,” “potentially,” or “possibly,” which imply the tentativeness of the presented conclusions (e.g., “The study may indicate that playing violent video games could lead to a higher level of aggression”). The use of these linguistic elements, which act as qualifiers of the given statements, is called hedging […]. Besides lexical hedges, the preliminary nature of the conclusions can also be indicated by additional information on the limitations of the presented study (e.g., with references to the limited generalizability of the findings), which would be a more explicit way of expressing uncertainty. Both types of hedges have been referred to as forms of powerless language. – Winter et al. 2015

To determine the effects of powerful vs. powerless language in scientific articles, this study tested four different versions of a blog article about violent video games. The first contained a neutral one-sided message: “An experimental study showed that realistic games with violent contents can raise the player’s level of aggression." The second contained a one-sided and assertive message about the danger of violent games, using terms such as “without a doubt,” “recent studies clearly demonstrate that... ” and “highly dangerous."

"According to Joachim Zeis, media psychologist and expert on media violence, it is unequivocally clear that ‘encouraging robbing and killing in the virtual world due to the lack of sanctions is problematic without a doubt and has an extremely dangerous influence on the development of young people.'" - One-sided assertive message

The third blog article version contained a one-sided but hedged message about findings related to violent computer game effects on children, using terms such as "partly," "potential danger," and "could." This version also included study limitations, such as: "It has to be mentioned that this study only compared three specific games, meaning that there are still open questions."

The final blog article version looked a lot like the one-sided hedged article but contained a two-sided message outlining the potential positive effects of computer games as well as the negative ones:

"However, it should be noted that computer games are not an inevitable cause of violence and antisocial behavior. On the contrary, they sometimes have a high educational potential and can have a positive impact. In a study conducted by the Munich Institute of Media Education it was shown that computer games promote feelings of competence and positively affect the ability to make moral judgments, perception and attention, sensorimotor coordination, emotional self-control as well as players’ critical self-reflection." - Two-sided message

Methods

The study consisted of an experiment with 82 participants (67 female, 15 male). The experiment was addressed at people who have children between the ages of 0 and 18 years, and participants (recruited via online forums) were asked to read a (fake) blog article about scientific findings related to violent computer games. The survey experiment was administered via the survey software https://www.soscisurvey.de/.

Findings

Participants found the blog article to be relatively credible, with no major differences between the different versions.

Readers of the two-sided version of the blog article, which presented evidence of both positive as well as negative effects of violent games, expressed a less critical and more moderate view on computer games than readers of the neutral one-sided blog post. We might have expected this to happen - if I tell you that computer games have both positive and negative effects, you'll probably be less likely to ban computer games in your household than if I only tell you about negative effects.

However, oddly enough, the assertive one-sided version of the blog article was less persuasive then the one-sided neutral version.