The Pilgrim Fathers of Massachusetts' Plymouth Colony shared their first Thanksgiving with their Indian neighbors in what social scientists today would call a "cross-cultural event."

Both the Pilgrims and the Indians took an ethnocentric view of their world. They were, like most people, certain their way of life was divinely ordained, and that those who differed were either primitive or very, very strange.

Neither, however, felt compelled to convert the other; tradition tells us each group brought its own foods and customs to share at that early American harvest celebration.

Each year several hundred international students at area universities and language schools indicate an interest in joining families for a holiday meal (a contemporary cross-cultural event right in your own home).

American hosts with a young adult in their own family will recognize many similarities. Their guest has probably already picked up the idioms, attire and egalitarianism of his American peers, and is very serious about his studies and chosen career.

"It is typical of Americans to look for the similarities first," says I. Robert Kohls, chief of the International Communications Agency training division, "but it's the differences that are more fun."

Those differences also can be confusing.

Former Soviet Premier Khrushchev, for example, found that Americans interpreted the Russian handclasp over the head as a sign of superiority rather than -- as intended -- friendship. Other classic examples of gesture confusion are the two-fingered V-for-victory and the A-okay circle made with the thumb and forefinger -- both strong insults in Latin cultures.

Or ask a Moslem how he would react to having an American acquaintance put his feet up, exposing the soles of the shoe.

Some students come from so-called noncontact cultures and may be uncomfortable with hearty handshakes, friendly backpats, or public kissing of any kind. Other cultural groups value togetherness at meals, but consider conversation a major distraction. Students used to such patterns may be uncomfortable with attempts to draw them into dinner-table dialogues.

Other differences -- less obvious, but real -- center around learning to cope with such cultural changes as moving from strong family authority to independent responsibility, from peer cooperation to classroom competition, from the analogous thought patterns of the Chinese to the inductive/deductive logic of the West. The list is long and "culture specific," varying with the part of the world your guest calls home.

It is these differences that bring on the period of stress known as culture shock, well known also to Americans abroad: too much change, too fast, for the psyche to cope. Culture shock often sets in about three or four months after arrival in a new land.

While host-family organizations stress that tolerance and good will are your most important assets, they do suggest a few guidelines for families who have not had previous experience with international guests:

* Do a little homework along with the housework. Have the children find your guest's home country on the map and learn a bit about the topography and ethnology, language and literature, even the birds and the beasts if those are family interests.

* Honor your guest, if possible, by learning a few phrases of his language. Also, something of his educational system, current economic progress in his country and cultural highlights of its past. The embassies are good sources of printed information, and so are the magazines put out by such groups as The Asia Society and the Organization of American States.

* Try to talk through ahead of time what you want to communicate about your family and your home. Volunteer families often will represent the particularly American style of "social-centered home," characterized as open and informal, the entire residence almost a clubhouse for individual family members. Your guest, however, most likely comes from the type of home classified as "authority-centered." Such homes have more structured family relationships, marked divisions between family and company areas and formal manners for those special occasions when guests are on hand.

Student visitors from such backgrounds may be reserved about suggestions to make themselves at home, help themselves to snacks or lend a hand in the kitchen.

(A note on conducting a house tour: While host organizations realize that visitors are curious about how Americans live, they recommend emphasizing family activities rather than family belongings.)

* If possible, get acquainted ahead of time. A phone call and an invitation to meet for coffee or a soft drink at the campus cafeteria make a good start. If your student drives, you can take him a map and directions for finding your home. Like any guest, he will appreciate knowing who else will be there and how formal the occasion will be. You might suggest he bring family photographs or tapes of music from home.

You might make a follow-up call Thanksgiving morning to be sure everything is on schedule. Like newcomers in any land, your guest may need a little reassurance.

While your relatives may be inclined to discuss their athletic triumphs or surgical tribulations during the day, your international guest will be most interested in learning how the family functions -- from the ceremonies of birth, marriage and death, to changes in careers and roles at home.

And do help your guest understand even more about this country by telling him about your immigrant ancestors, and how they made their way in the New World.