THIS YEAR the committee that selects the winners of the Nobel Peace Prize did its work exceptionally well. It awarded the 1976 prize, which had not been awarded last year, to Betty Williams and Mairead Corrigan, the young Ulster women who inspired the formation of the Northern Ireland Peace Movement. It awarded this year's prize to Amnesty International, the 16-year-old organization that works for the release of "prisoners of conscience" all over the world. There is something very fitting about the conjunction of these two awards. The recipients have a great deal in common, and in important ways they also complement each other.

What Amnesty International and the Northern Ireland Peace Movement have in common is founders, leaders and members who have no use for the abstract and the grandiose in their work, but who are given instead to modest, practical and - yes - heroic here-and-now efforts. They are dedicated to relieving human anguish in the situations they have chosen to address. They are each, in slightly different senses, apolitical, insisting that neither armed violence in the one case, nor political repression in the other, is an acceptable instrument of policy - irrespective of whether you happen to share the goals of the policy or not.

The two newly honored groups also have this in common: What success they have achieved is a tribute to the capacity of ordinary individual citizens to make a difference. The Nobel committee underscored the point in giving the 1976 award to the two Irish women whose revulsion against violence in Ulster was brought into focus by the death of three Belfast children, hit by a careering IRA car whose driver had just been killed by British bullets. "Mairead Corrigan and Betty Williams," the committee said, "acted from a deep conviction that the individual person can make a meaningful contribution for peace . . ."

Amnesty International likewise had its origin in the determination of a few hardy souls to do something about the plight of people who were suffering at the hands of various governments for their political or religious views or because of their race or ethnic background. In 16 years it has acquired over 100,000 members, is represented in almost 80 countries and has managed, to its credit, to get on all the right enemies-lists - those of repressor governments of every political stripe in every part of the world. But in the course of this expansion, it has made a point of remaining faithful to its simple, direct techniques, a kind of human-rights "buddy system" whereby individual members accept responsibility for a few individual prisoners and organize the work in their behalf.

So you could say that these two organizations share a special spirit and a special outlook. But there is a difference, too. The Irish group is above all else - as it must be - the sworn enemy of physical violence, Amnesty International the sworn enemy of political repression. Yes, the lines do cross, and neither group is indifferent to the principal concern of the other. We observe this distinction only by way of noting that the Nobel Committee, by this particular choice of recipients, has made an important statement of its own. It has said that peace is more than the absence of conventional war and that tranquillity achieved by locking up dissidents is no peace at all.