“You’ve won the internet,” one Twitter user congratulated the University of Reading after it dished up a hearty dose of social media sass. The “winning” tweet was a robust dismissal of critics of the university’s refugee scholarship scheme.

“We’ve had feedback over the last week that some people are unhappy with our plan to offer up to 14 scholarships to refugees living in the local area. To these people, we would like to say: Tough. Jog on.” A similar message was posted on the university’s Facebook page.

On the one hand, it’s great to see an academic institution that’s proud to support refugees, to act on its values and to express all of this with a bit of personality. The 68,000 likes, together with delighted responses on social media, show just how satisfying a snarky put-down can be if it’s issued by a member of your tribe.

These kinds of righteous snubs are rife on social media. But while they can be satisfying if we agree with the sentiment, they don’t actually move anything forward. Stating that you are right and other people are wrong is not a strategy for change. In fact, there’s solid evidence to suggest that talking in this way can do damage: entrenching divisions, compounding hostility and turning people away from your cause and position.

Social media moments such as this don’t just stay in social media. They spill over into the news and the broader public discourse, where they shape attitudes and beliefs over time. While Twitter might feel like a playground for the quick-witted, deliberately provocative tweets like this one can have far-reaching effects.

First, in calling out the opinions and beliefs it finds problematic, the University of Reading may well be further entrenching the very views it’s seeking to dismiss. Beliefs and ideas are like muscles – when an idea is invoked, it is flexed and strengthened, whether that is the intention or not.

Second, by telling people they are wrong, the university is driving people further into their tribes, fuelling cultural divisions and alienating anyone who doesn’t strongly support its stance. Most people aren’t firmly fixed in their attitudes towards refugees. In fact, most people have mixed feelings about most issues. Strident projections of moral superiority shine an unwelcome and uncomfortable light on this ideological indecision. They prompt anyone who’s undecided to back away to avoid feeling awkward and exposed. Our brains work hard to protect us from uncomfortable thoughts and feelings – and this cognitive immune system kicks in when we feel judged or unsure of our views.

Public attitudes towards refugees and migrants matter. They can cultivate a fertile ground for compassionate policy making and inclusive behaviour, or they can legitimise hostile environments. Public attitudes in this space are also complicated. It is hard to influence public thinking in a meaningful way. Even the genuine public outcry over the government’s treatment of the Windrush migrants is unlikely to have shifted public thinking about immigration more broadly.

Generally speaking, changing public thinking requires us to celebrate all that we share, not draw attention to the dividing lines. We can learn a lot from the handling of recent polarised debates on marriage equality and abortion in the Republic of Ireland. Campaigners built on – and continue to build on – shared values and ideals. They speak to the moral shared ground instead of casting aspersions from the moral high ground. It’s not about stripping out the conviction or substance, or about dialling down passion. It’s about communicating in a way that is compassionate, inclusive and is actually effective.

We don’t win the internet – or anything else – by stirring divisions and telling people they are wrong. We don’t win with snarky put-downs from the moral high ground. If belittling tweets were the answer to our problems, the world might be in different shape. While the University of Reading might have earned itself a place in this week’s Twitter in-crowd, it is likely to be doing harm to the cause it aims to champion.

• Nicky Hawkins is a communications strategist for the FrameWorks Institute