In myriad subtle ways the daily lives of the residents of Muncie, Indiana, have changed a lot since September 11 2001. This 70,000-strong town of many churches and increasingly little industry gained fame in the 20s as the subject of academic survey of the American heartlands called Middletown. Since then sociologists and pollsters have returned periodically to gauge the mood of Middle America. Geographically, it's slightly more than 600 miles from the recently renovated storefronts of its main street to the hollowed pit of Manhattan's ground zero. Culturally, it is like a different country.

"Most people in Muncie look at what happened in Washington and New York and think, that's a long way away," said Muncie mayor, Dan Canaan. "Those are things that might happen in the big city but not here."

On a national level the last two years have left some obvious scars. Three-quarters of Americans now see the world as a more dangerous place than it was 10 years ago, compared to 53% just before the terrorist attacks, according to a Pew research poll. A similar number believe that occasional acts of terrorism will be part of life in the future.

But in towns like Muncie, you can see only the occasional evidence of these new concerns. Most schools in the town have closed all their entrances bar one. The county building has a guard and a metal detector while the water treatment plant has a guard and concrete barrier. "Nobody thinks for a minute that Osama bin Laden is going to attack Muncie," said Mr Gonsell. "But terrorists might attack Chicago or Indianapolis and the fallout from that would affect us."

More evident are the popular public responses to those concerns. Behind the bar at the American Legion there is a red, white and blue neon sign declaring United We Stand. In the foyer of the city hall a large poster covered in American flags drawn by third-graders gives: "A salute to Muncie's heroes". On it the eight-year-olds have written messages to the soldiers saying: "Make us have peace" and "Thank you for going to war".

Muncie played host to many of the setpiece events that took place elsewhere in the country. Two restaurants changed the name of French fries to freedom fries; there was a pro- and anti-war demonstration both of which attracted about 75 people; the sign for the local mosque was destroyed; on national prayer day the Reverend William Keller, a local preacher who has presided over the event for the last 10 years, refused to share the pulpit with Muslims, Jews or any other religion.

But if some of these episodes revealed an ugly streak, the town's response to them showed an even greater atmosphere of tolerance - a core of local human decency in globally ugly times. After the incident at the mosque, Mr Rahman held a barbecue which attracted more than 200 neighbours. When the library hosted a session on understanding Islam there was standing room only. Even Mr Dalton is convinced that if he sat down with a Frenchman over a beer they would agree on more than they disagreed. The Rev Keller's stance prompted an alternative interfaith service that received twice the number that his did, even though it rained. "The things he said didn't surprise me," said Mr Rahman. "But the way people reacted did."

For a few people the changes have demanded significant alterations in their working lives. Mr Gonsell spends half an hour a day reading the New York Times and Washington Post to keep abreast with international news. In August 2001 he was pilloried in the local press for wasting taxpayers' money when he took the mayor and other key city employees to Mount Weather in Virginia for anti-terrorism training. That wouldn't happen now. "September 11 made my life more difficult because I have much greater workload," he said. "But it has also made it easier because people are far more receptive to training."

At the public library, staff shred records of who has been using the computers and purge the files recording which books have been taken out and returned each day. Under the Patriot Act they are obliged to hand what information they have over to the Homeland Security department if requested. Getting rid of them is the easiest way to avoid breaching confidentiality. "You don't have intellectual freedom if you have big brother breathing down your neck, looking at what you're reading and researching," said Ginny Nilles, the libraries director.

More pervasive than the changes in routine are the small alterations in human relations. Like most, Mr Dalton now "takes a lot more notice of Middle Easterners". But there is not just suspicion of "the other" but also each other. Ms Helms is careful with whom she shares her liberal criticisms. "I have got to a point where I'm very reluctant to make nasty remarks about the Bush administration with people I don't know. I like playing bridge so I just don't mention politics when I'm there because I don't know what the reaction will be."

But there have been similarly unpredictable responses from the other side. Mr Dalton said he has had arguments with his workmates on the railroad, many of whom were against the war in Iraq. "I don't think they know what they're talking about," he said. "There's a lot in this country ain't perfect but I don't think anybody has a better system than we do."

"The day when you would go out of your way to make a political statement are gone," said Joseph Losco, chairman of the town's Ball State University political science department. "I don't know if it's gone for ever but it's gone for now."

But in many ways September 11 did not so much change people's behaviour here as exaggerate certain aspects of it. In a straw poll of students in a European politics class at the university, five out of seven said they had displayed a flag following the attacks. But three of those were doing so already.

Ms Helms' friend and fellow traveller in the American Civil Liberties Union, Mr Carson Bennett, said their views never did go down well in Muncie. "But before they just thought you were wrong-headed. Now they question your patriotism."

Bangladeshi-born Mr Rahman, one of around 200 Muslims in the town, was no stranger to anti-Muslim discrimination on September 11. When he saw the second plane fly into the World Trade Centre he called his wife to tell her not to let his two children play outside.

The attacks made that vulnerability more intense. "The problem is they can put you in jail first and then ask why." When he joined a Muslim delegation to see his local congressman, Mike Pence, the politician put them on notice: "If there is another major event like 9/11 then you guys are in trouble."

Mr Rahman's response has not been to withdraw but to further engage in Muncie society. He is more likely to talk to his neighbours and colleagues now so they know who he is and what he believes in and they no longer have to fear the unknown. "September 11 made us concentrate on our lives in this country and get more involved in things like schools, hospitals and libraries," he said. "That's one of the positive things to come out of it."

Muncie may be small but it is not her metically sealed. Last week the local public radio station started broadcasting BBC reports (albeit between three and five in the morning) and three of the seven students said they now looked at foreign news sources and had travelled abroad.

True, according to Mr Losco, many of his students have never even been to Chicago, four hours drive away. But working class residents here have long been aware of the powerful impact the rest of the world can have on them since globalisation sent much of its industry to Mexico, leaving the university and the hospital as the town's two largest employers. "Having been through that economically there's a sense here that politically we're not going to lose our place in the world too. Because the world's a scary place."

Leader comment, page 27 theguardian.com/september11