It turns out that negative comments aren’t all bad: a new study finds that criticism of a product can actually boost sales significantly if the commenter is polite.

In a novel experimental study, a team of university researchers found that respondents were willing to pay 41% more for a wrist watch when it was surrounded by negative comments that couched their opinions in polite qualifiers like “”I don’t want to be mean, but…”

This means that attempting the near-impossible — curating a community of civil discourse in comment sections — could be a very lucrative strategy. Word-of-mouth communication is a fundamentally social endeavor. “Consumer-to-consumer communication is not simply a matter of trading facts and assessments,” explain the researchers [PDF] “Our research raises the intriguing possibility that brands might benefit when polite customers write reviews of their products — even when those reviews include negative opinions“.

The authors cite previous research that shows how critical reviews are perceived “as more intelligent, competent, and higher in expertise – in other words, more credible.” Intuitively, this makes a lot of sense. Snakeoil salesmen invoke our knee-jerk BS meters precisely because we know that nothing is all rainbows and sunshine. A bit of honesty can put our fears to rest.

Before community managers start courting people who don’t like their products, it’s important to note that negative comments often come with a rating. And, negative ratings can tank sales. One study found that a simple half-star difference on Yelp can make or break a restaurant. 5-stars was associated with 30-50% more sell-out seating during peak eating hours.

So, there’s some important nuance to the art of ratings. Getting the tone of community right can mean a lot of money.