If you asked Thomas Frederickson where he got his black pearl jewelry, his answer might surprise you: His friend Lehi Tehiva brought it to him from Tahiti. Thomas met Lehi while serving on a two-year mission for the Church of Jesus Christ of Latter-Day Saints. Lehi typically visits Thomas’ family in Utah two or three times a year, where they cook big fish dinners, reminisce about their trips and play music together.

What would have sparked this kind of trans-global relationship? It turns out:

The Pacific Islands have unusually high rates of membership in the Mormon church.

Statistics about religious affiliation are notoriously difficult to measure and often rely on self-reported numbers. In most countries, Mormons make up less than 2 percent of the population, according to church figures. However, some scholars estimate 36 percent of Samoa’s population belongs to the Church of Jesus Christ of Latter-Day Saints, according to the 2014 edition of Reaching the Nations: International LDS Church Growth Almanac, by David G. Stewart Jr. and Matthew Martinich. The book cites even more church members in Tonga — 45 percent of the population, the highest per capita rate in the world.

Many scholars argue that those statistics don’t account for inactive members, which could be one reason that church-generated numbers differ from census and other data, says Max Perry Mueller, assistant professor of classics and religious studies at the University of Nebraska-Lincoln. The U.S.-based World Population Review, for example, shows Samoa is 15 percent Mormon — still an impressive number, but far short of the church’s figure of 40 percent.

Pacific Islanders have been receptive to Mormon customs, but their culture hasn’t influenced church doctrine in return.

Still, what led these communities to adopt the faith with such gusto and why has the tradition endured? Protestant missionaries had introduced Christianity to French Polynesia in 1797 and to Hawaii in 1820, making the Pacific Islands among the first regions to be evangelized. Joseph Smith followed suit, dispatching missionaries to the scattered archipelagos in 1843, just 13 years after he founded the Mormon church.

The islands of Hawaii were long regarded as the most receptive, according to The Church in the South Pacific, by R. Lanier Britsch. And Hawaiian was the first non-European language into which the Book of Mormon was translated, in 1855, according to In His Own Language, by Kai A. Andersen. While the church maintains missionary efforts all over the world, it focuses on areas where results are better, says Kristine Frederickson, a professor of church history at Brigham Young University in Salt Lake City and Thomas’ mother (the church founded and funds BYU).

Another reason for the church’s success in the South Pacific may be a shared cultural emphasis on family. Church doctrine holds that families can be bound together for eternity, according to Richard Hunter, Pacific area director of public affairs for the church. Other Christian sects consider death as a parting point for family members, notes Sapele Faalogo, a Samoan church member.

The Pacific Islanders Thomas Frederickson met emphasized the importance of family. During his mission, he often saw grandchildren, aunts and uncles living together across two or three generations. Although each individual ultimately decides if he or she wants to become baptized, many families convert together. Communities in the Pacific Islands are also influenced by village chiefs, according to Hunter. If chiefs convert, others follow their lead, although church doctrine holds that conversion is an individual matter.

Pacific Islanders have been receptive to Mormon customs, but their culture hasn’t influenced church doctrine in return. The church’s teachings remain uniform throughout the world, so if a custom clashes with the Mormon rulebook but an individual still wants to convert, the church doesn’t let the local stuff slide. In Tahiti, for example, it was common for partners to live together and raise a family without marrying, Frederickson says. To receive baptism in the Mormon church, though, the couple had to get on board with the rules regarding premarital chastity and tying the knot.

However, the church might be less keen to admit historical missionary efforts weren’t equally welcoming to all countries and cultures. This year marks the 40th anniversary of the 1978 change in church doctrine that opened up the priesthood to all males regardless of their ethnic origin, reversing a policy that had been in place since at least the early 1850s, according to Mueller. Before this date, men and women of African descent were excluded from the priesthood and barred from accessing the temple, where the most sacred rituals of the church took place, like spouses becoming bound for time and all eternity. “They were very much second-class members of the body of Christ,” Mueller says.

Mueller emphasizes that the racial underpinnings of Mormon beliefs stem from their conceptions about ancient lineage. Mormons believed that Africans descended from a “cursed people,” but believed that Samoans and others living in the Pacific Islands descended from “favored, or blessed, people,” he says.

On top of this, the church hasn’t proved its ability to celebrate cultures respectfully. Beginning in 2006, the BYU football team and Utah high schools performed a version of the traditional New Zealand Māori Haka dance before games, attracting criticism, including from the vice president at BYU–Hawaii, who is Māori. White American Mormons have an affinity for Native American culture and Pacific Islander culture, Mueller says. “They revere it to the point where they have been accused of culturally appropriating, collapsing the identity between Mormon and Pacific Islander.”

But not always. Just ask Thomas and Lehi.