If any single issue is the decisive yardstick by which to measure the Third World's preferences in the U.S. presidential election, it may be human rights.

Because Ronald Reagan -- rightly or wrongly -- is widely perceived as a man who would place less emphasis on human rights as a foreign policy issue, Washington Post correspondents in the developing world reported, officials in a number of Third World countries seem to be leaning to the former California governor.

This is particularly true of many military rulers in Latin America. For the same reason, many dissidents in these countries said they preferred a second term for President Carter, who they hope would continue to apply pressure on countries such as Chile, Argentina, Bolivia and Guatemala to improve their record on human rights.

In africa -- where many governments also have been cited for human-rights violations -- there is a more decisive issue. There, the Carter administration has made enormous strides in dealing with the black-ruled governments and has criticized South Africa for its continuing segregationist policies of apartheid. Consequently, comments from Africa suggest that the black-ruled countries would be overwhelmingly for Carter and Pretoria overwhelmingly for Reagan.

Correspondent Caryle Murphy reports that the Carter administration's backing of the peace settlement in Zimbabwe did much to seal these sentiments in both parts of Africa.

In Southeast Asia and the Philippines, William Chapman reports, some officials seem to prefer Reagan because of the rights issue, but other prefer Carter in hopes that current regional security plans can be continued. As with the European and Far East countries surveyed yesterday, however, support for either candidate was generally subdued and unenthusiastic.

Perhaps no part of the developing world is more important strategically than the Middle East, as the Persian Gulf war has demonstrated anew.

Correspondent William Claiborne reports that many Israelis view U.S. policy in an East-West context. As a result, many Israelis prefer Carter, who they feel would take a tougher line against the Soviets and who would resist pressure to include the Palestine Liberation Organization in the Middle East process.

In Egypt, correspondent David B. Ottaway encountered more apparent support for Carter, although the official line is that "it is not so serious whether Carter [or Reagan] is in the White House next," as a Foreign Ministry spokesman put it.

Nevertheless, this spokesman said, "Camp David is Carter's baby." Although some Arab officials expressed fears that Reagan would back Israel more unequivocally, many believe he would alter views expressed in the campaign once confronted with the region's realities.

Mainstream Arab opinion seems weighted toward Carter, with the possible exception of the Palestinians and other opponents of the Camp David accords, which, as one PLO official put it, offer the Palestinians "eternal occupation."

It must be stressed that these are not the results of a scientific survey, but a sampling of government leaders, bureaucrats and the general public abroad. Generally, even the best informed of this group would have a more limited view of the candidates and their views than the American public has; this exercise is designed to help acquaint the reader with some of the currents of thought our correspondents have encountered.