'Everything was going well. He could not accept this, as he was afraid that someone would eventually discover the truth about him . . . his true nature." This line, spoken by the narrator, provides the title for Willie Doherty's multiscreen video installation True Nature, which explores both the insecurity of emigrant identities and the diaspora's romanticised views of Ireland.

Best known for what Declan Long has described as his reflections on the fractured society of the North, Doherty is arguably the most significant Northern Irish artist of his generation.

Commissioned by the Renaissance Society at the University of Chicago, and first exhibited there in 1999, True Nature marked a thematic departure for the Derry-based artist from works rooted in the Troubles. It features journalistic video footage of interviews that Doherty conducted in Chicago with second- and third-generation Irish-Americans who had never visited Ireland.

The narrator’s voice, speaking of the dislocation and insecurity of the emigrant, is interwoven with extracts from the interviews. The images, projected on five large screens arranged so that they cannot all be viewed simultaneously, combine urban scenes of Chicago with shots of rugged Irish landscapes, medieval ruins and waves crashing on a rocky shore. The images of Ireland were shot when Doherty returned from the US and went searching for scenes that lived up to the Irish-Americans’ nostalgic perceptions.

Like much of Doherty's work, True Nature explores ideas of place, belonging and the constructed nature of history and identity. As Carolyn Christov-Bakargiev has observed, "There is a dreamy quality to the work, with long slow fades from one sequence into another and stories overlapping in a slightly chaotic manner." This fragmentation of narrative and structure echoes the diaspora's half-formed ideas of Ireland, constructed from photographs, travel posters, media imagery and family tales: a cocktail of nostalgia and myth.

True Nature is shaped by the period of its conception at the end of the millennium. An obvious time for reflection and self-appraisal, this was also a moment when the image of Ireland, both at home and abroad, was in flux. The Celtic Tiger was in its prime, and Ireland was being transformed from a poor country on the edge of Europe to a (short-lived) economic miracle.

Sexual-abuse scandals had dethroned the Catholic Church from its position as the moral compass of the Republic. Irish emigrants who had left in the 1980s for London and New York were being coaxed home by new opportunities. With them they brought liberal attitudes, international perspectives and cosmopolitan tastes. In the North the Belfast Agreement, signed in 1998, was the most significant move towards peace and the normalisation of society for more than 30 years.

Although these changes brought progress and possibilities, they also helped to cause a crisis of identity not dissimilar to the insecurity of the emigrant voiced in True Nature.

In contrast to the reality of an increasingly globalised and diverse Ireland, the perceptions that Doherty encountered in Chicago were romanticised and decades out of date. The gulf between the diaspora's perceptions and the reality of life in Ireland raised issues of identity and representation that have been core themes of Doherty's art from his early black-and-white photographs, such as The Walls (1987), to his Turner Prize-nominated video installation Re-Run (2002). Although Re-Run features looped images of a suited man running in terror across Craigavon Bridge in Derry, it has strong resonances of events in Manhattan on September 11th, 2001.

Like Re-Run, True Nature demonstrates convincingly that Doherty's strength lies in his ability to make work conceived in a particular time and place comprehensible and poignant beyond the limits of that context.

You can read more about this week's artwork in the Royal Irish Academy's Art and Architecture of Ireland; ria.ie