Why are physicists thick-skinned but biologists run for the hills when the comment trolls invariably appear?  It may help to be arcane and complex - it's harder to troll hard sciences. Everyone feels like they know some biology but good luck to casual readers trying to debunk rare B_s decays in a high energy physics paper.

But in biology you will invariably get comments like...

"How much did Monsanto pay you to write this?"

and

"You can't prove this is safe"

...which can be frustrating. Brian Dunning at SkepticBlog even coined a term for it - Argumentum ad Monsantium - and has a hilarious list going back to 2008 of when it was used against him, even when he was not talking about biotech at all. It is just the go-to claim for people who hate biological science, the same way 'scientists used to talk about an ice age in the 1970s' is used by detractors of climate science.

The next big culture war is nanotechnology and it is going to make GMOs and pharmaceutical research look like a societal walk in the park. Unfortunately, for people just trying to learn about new research or technology, the tone of comments can be such a turn-off that it will skew the perception of the science itself. Basically, the trolls win just by using fear, doubt and derision. In that sense, as much as it is anathema to Science 2.0, it is sometimes better to just shut off comments.

An online experiment sampled a representative cross section of 2,338 Americans where the civility of blog comments was manipulated, like introducing name-calling into commentary tacked onto an otherwise balanced newspaper blog post. Results showed that comments could elicit either lower or higher perceptions of risk, depending on one's predisposition to the science of nanotechnology.

"It seems we don't really have a clear social norm about what is expected online," said Dominique Brossard, a University of Wisconsin-Madison professor of Life Science Communication, contrasting online forums with public meetings where prescribed decorum helps keep discussion civil. "In the case of blog postings, it's the Wild West."

For rapidly developing nanotechnology, a technology already built into more than 1,300 consumer products, exposure to uncivil online comments is one of several variables that can directly influence the perception of risk associated with it.

Some results were a little odd. Highly religious readers were more likely to see nanotechnology as risky when exposed to rude comments than less religious readers. So maybe less religious people are used to rudeness.

But even simple disagreement in posts can also sway perception: "Overt disagreement adds another layer. It influences the conversation," Brossard said.

UW-Madison Life Sciences Communication Professor Dietram Scheufele, another of the study's co-authors, notes that the Web is a primary destination for people looking for detailed information and discussion on aspects of science and technology. Because of that trend, "studies of online media are becoming increasingly important, but understanding the online information environment is particularly important for issues of science and technology."

Article: Journal of Computer-Mediated Communication, no live online version yet.