It is one of the truisms of the theatre that plays are not the property of their authors or performers but are created by their audiences. But audiences are by definition unstable creatures, formed by time, place and assumptions. This is why it is often so intriguing to see familiar work out of its original context. This is particularly the case with work that uses a very specific Irish sense of humour.

One of the most interesting experiences I had when I was reviewing theatre in New York a decade ago was the arrival of a play and production I already knew very well. The Druid production of Martin McDonagh’s The Beauty Queen of Leenane arrived at the Atlantic theatre off-Broadway, with its original Galway cast and designs. As is the practice for critics in New York, I went to a preview performance. I was therefore seeing the play with an audience that had not been influenced by reviews.

I left pretty sure that the whole thing was going to be a bit of a disaster. It was not that the production was any less powerful than it had been in Ireland, but that it was missing that most intangible but indispensable element: its connection to the audience. What was happening was that the New Yorkers seemed deeply uncertain about how to respond to McDonagh’s blackly comic world. Some people were laughing. Some were disturbed that others were laughing. Some were simply disturbed. There was a deep unease that seemed to seep into the play itself, turning what is a brilliant piece of stagecraft into a work that, on the contrary, was verging on the gauche.

I saw the show again the next week after the reviews had appeared. All of them had said how funny the play is. Now, the audience was laughing its head off in all the right places. It was as if it had been given permission to find the play both funny and tragic, both outrageously playful and deeply cruel. And, of course, from there on, the production became a roaring success, transferred to Broadway and won four Tony awards.

I thought of this experience last weekend when I happened to catch another Druid success, Enda Walsh’s The Walworth Farce, on the epic tour that will take it, on and off, from Galway in 2006 to Australia and New Zealand in 2010: 209 performances in 22 cities. I have seen it only in Ireland before, but this time it was playing in the Walker Art Centre in Minneapolis. Again, the context seemed to be one in which most of the audience had no great sense of what to expect, knowing little of Walsh, Druid or, indeed, Ireland.

What struck me most forcibly is how much darker the play seems with this kind of non-Irish audience than it does at home. It is not, of course, that Walworth is an exercise in gentle Irish whimsy in any context. Walsh’s tale of a demented Irish father and his two sons in a London flat, playing out the same weird farce over and over, is pretty ferocious in Dublin, Cork or Galway.

It deals with murder, madness, and the locked-in Irish family. It subverts the whole idea of the Irish gift of storytelling as a cultural blessing and presents it as a psychotic reaction to a reality that must be avoided and denied. No one would ever mistake Walsh for Lady Gregory.

In Ireland, though, we’re used to walking a fine line between the grotesque and the hilarious, to having one eye blinded by tears of laughter and the other covered to shield it from the horror. With plays like Beauty Queen or Walworth, Irish audiences can take the idea that the comedy and the horror are wrapped up in each other and that it’s therefore okay to emphasise first one and then the other. There’s a graduated slide from the comfort of laughter to the discomfort of madness.

Watching Walworth in Minneapolis, however, this slow shift seems absent. The play seems pretty damned disturbing from the start. In a sense, the American audience has a much more rational approach. This whole spectacle of the crazed and tyrannical father and his enslaved sons playing out their hysterical and joyless farce seems pretty far out there from the very beginning – which, of course, it is. It is not that the audience doesn’t laugh at all – the brilliant clowning of Mikel Murfi’s production is as irresistible as ever in this version with Michael Glenn Murphy, Tadhg Murphy and Raymond Scannell. But the sense of deep disturbance, of shock even, is a much earlier and more potent presence.

Some of this has to do with the specifics of American mores: Walsh’s use of blackface in the latter stages of the play is much more transgressive in the American than in the Irish context. But a lot of it is rooted in the way Irish audiences have been formed. It is not just that a play like Walworth can be recognised in Ireland as, at one level, a game with inherited tropes, relating, for example, to Tom Murphy’s A Whistle in the Dark and Bailegangaire. It’s also that there’s a broader cultural impulse, expressed both inside and outside the theatre, of deadpan humour in which the game is to guess whether something is serious or not.

Seeing the play with people who are not protected from its darkness by these inherited defences makes it somewhat less complex but in some respects more powerful. There was a rawness to the experience in Minneapolis that was not there in Ireland. The audience was utterly gripped by the play and rose to its feet in spontaneous acclaim at the end, but seemed to experience it almost as an assault. I actually envied that state of being less knowing, less shielded by a learned unshockability, in which it was possible to experience the full force of an unpleasant truth about Ireland.