On many fronts, scientists continue to be frustrated by the public's unwillingness to accept their conclusions. On issues ranging from Ebola to climate change, their impulse is often to re-state their case in ever-more-vigorous terms, forcefully noting that there is no serious doubt about their assertions.

Newly published research from Germany suggests that sort of language may, in fact, be counterproductive.

In a small online study, participants who read about another hot-button topic—the effects of computer games on children—were more skeptical "when statements were presented as overly certain," according to a research team led by Stephan Winter of the University of Duisberg-Essen. Its research is published in the Journal of Language and Social Psychology.

"Readers were not persuaded by powerful formulations which described scientific evidence as very certain, but seemed to be skeptical when information was presented as too simple."

The 78 participants (with a median age of 40) read one of four versions of a blog post describing scientific findings regarding video-game play. One group read a one-sided version of the argument, which was presented using neutral terms, such as: "An experimental study showed that realistic games with violent content can raise the player's level of aggression."

Another group read a more assertive version of the same, with terms such as "clearly demonstrate that" and "without a doubt" included in the text. A third group read a hedged version of the statement, which included terms such as "potential danger" and "there are still open questions." The others read a more balanced statement, in which potentially positive aspects of video-game play were listed alongside the dangers.

While participants rated each version of the blog post as relatively credible, they responded to them in different ways. Not surprisingly, "participants who received the one-sided version in the neutral mode of presentation had a more negative attitude toward the effects of violent computer games than readers of the two-sided version."

More interestingly, the version using the hedged terms "did not lead to a significantly less negative attitude" toward the games. The qualifiers did not register strongly enough with readers to influence their opinions.

Most importantly, "readers of the assertive version expressed a significantly less negative attitude toward computer games than readers of the neutrally presented text," the researchers write. "This means that readers were not persuaded by powerful formulations which described scientific evidence as very certain, but seemed to be skeptical when information was presented as too simple."

In other words, people tend to believe that nothing in science is too certain, and the insistence that a debate is closed is treated with considerable skepticism.

As noted, this was a small study, one that needs to be duplicated on a larger scale, preferably with additional issues addressed. But if its results hold up, it suggests scientists who use assertions of near-certainty to either comfort us or scare us into action may actually be hardening resistance to their conclusions.

At least, that's quite plausible. We're honestly not certain.