This is one of the findings in a new book, Community Relations Work with Pre-School Children, by Dr Paul Connolly of the University of Ulster.
By the age of three, he writes, children may develop negative attitudes towards such categories, and by the time they are five they may develop an increasingly negative attitude towards figures such as Catholic priests and Protestant ministers.
Against such a background, the biggest surprise is not that the politicians are taking so long to reach final agreement but that they have come so far. They are now grappling with essentially the last piece of the jigsaw.
Those negative attitudes, instilled almost literally in the cradle, lie at the heart of the decommissioning argument and will endure for many decades. Any deal will be based not on newly-realised bonds of friendship but on calculation and a sense that the opportunity has come to draw a line under the troubles.
This boils down to a shared realisation that Northern Ireland will either continue to be run directly from London or will be administered by a cross-community devolved government.
Some believe Sinn Fein would prefer unionists to storm out of the process; others think the unionists still hanker after an executive without republicans. The signs are that both these assessments are wrong, and that the leaderships on both sides are aiming for an inclusive executive.
It is this sense of common purpose which has kept the former US senator George Mitchell's review of the Good Friday Agreement on the rails. The negative attitudes, however, have had their effect, prolonging the review into a nine-week marathon.
The two main protagonists, the Ulster Unionists and Sinn Fein, have grown used to dealing with each other face to face. One would be surprised to hear David Trimble, the Ulster Unionist leader, and Gerry Adams, the leader of Sinn Fein, emerging to say they had learnt to trust each other, but they have at least become accustomed to doing serious business together.
If a deal does emerge, it will not be done on the basis of a handshake. Whatever formula they come up with is likely be festooned with guarantees, fail-safe mechanisms, penalties,confidence-building measures and the like. It is also fair to assume that success will not produce a single dazzling breakthrough. It is more likely to take the form of a series of carefully choreographed steps, by which republicans indicate that their war is over as unionists promise to accept them in government.
In other words, it would be a process, to use the word which has described the long and tortuous path towards peace that has now lasted almost a decade. It was a long war, and the business of bringing it to an end is taking a long time.
The peace process has persisted, despite being written off many times by pessimists and by its opponents. Its eventual success would allow a start to be made on convincing the parents of those two-year-olds that the other side are not bogey men but real people.Reuse content