The Church of Jesus Christ of Latter-day Saints has been in the headlines recently after a series of essays were posted on the church's "Gospel Topics" website that detailed much about the its history with polygamy (see here, here, and here). Most notably, these essays included admissions that the Church's founder Joseph Smith had up to 40 wives (at least one as young as 14) and that among these were women who were already married to other men.
While most of this information was not new to academics and scholars of Mormon history, much was likely surprising news to many of the Church's rank and file membership. While the institutional Mormon educational curriculum does contains some references to Joseph Smith's "plural marriages," full details about the extent and nature of these marriages, including his experiments with polyandry, are absent from the standard Sunday School curriculum (see here and here for an overview). Thus, these were surprising - if not shocking - revelations by the LDS Church to many of its members.
Other Mormons, however, have downplayed the novelty of the information contained in these essays. They have argued that the LDS Church has never intentionally hidden this information and that Mormons have a responsibility to study their own history (see here, here, and here). Thus, they blame the Mormon rank and file themselves for their ignorance on these matters.
These arguments, however, stand in contrast to statements made by faithful and well-respected Mormon historians such as Richard Bushman, who explained on a recent MSNBC interview: "The fact of the matter is the Church has not been discussing polygamy, it's tried to put it in the past, to sort of forget about it. So church members can grow up without having any real understanding that Joseph Smith [had any wives other than] Emma." Placing the blame on the members themselves also ignores the fact that Mormons who publicly discussed the messier details of polygamy and other historical issues have often been marginalized and sometimes even excommunicated by Church leaders in the not-so-distant past. For instance, D. Michael Quinn was excommunicated in 1993 in part for publishing research detailing how polygamy continued in Utah even after its termination had been officially announced by LDS President Wilford Woodruff in 1890. (It is noteworthy that one of the recent polygamy essays also describe how polygamy continued in Utah even after it was officially discontinued in 1890.) Also, in 1989 church leaders warned members about "alternate voices," which was widely understood to mean non-Church approved sources of information about Mormon doctrine and history. The consequences of these actions are still felt today as many faithful Mormons are deeply suspicious of any information concerning Church history that comes from outside the Church institutional structure, or any information that contradicts the sanitized historical narrative that the Church has taught its members over the last several decades.
Some may wonder how many Mormons were aware, before the release of these essays, that Joseph Smith had 40 wives (some as young as 14) or that he married women who were already married to other men. To my knowledge, there is no existing survey evidence that can definitively answer that question one way or another. However, a 2012 survey conducted by David Campbell, Quin Monson, and John Green, measured levels of Mormon awareness of another thorny issue from Mormon history: its ban on members of African descent from being ordained to the priesthood which ended in 1978.
The Mormon priesthood ban is the subject of one of the first historical essays to have been published by the Church in late 2013. It explains that during the early 20th century, Mormon leaders taught that the priesthood ban was a direct consequence of blacks having been "less valiant" in their pre-earth life. This was a popular teaching in Mormon culture for several decades, although it was quickly de-emphasized after the priesthood ban was lifted in 1978. Although it was certainly downplayed for some reasons, this teaching was officially disavowed in 2013 when the LDS Church's essay on race and the priesthood explicitly stated: "Today, the Church disavows the theories advanced in the past that black skin is a sign of divine disfavor or curse, or that it reflects unrighteous actions in a premortal life; that mixed-race marriages are a sin; or that blacks or people of any other race or ethnicity are inferior in any way to anyone else."
A year before this official disavowal came, the 2012 Peculiar People Survey asked American Mormons if they had ever heard of the following: "In the past, some Mormons have said that blacks had to wait to hold the priesthood because they were less valiant in the war in heaven, or the premortal existence." In this survey, only 45% of Mormons said that they had heard of this teaching, of whom 22% said that they agreed with it. That left only 10% of Americans Mormons who had both heard about it and agreed with it. (See Seeking the Promised Land, pgs. 58-62.) As more years pass and the LDS Church continues to grow both through conversions and generational replacement, it is likely that this number will only continue to shrink in the future.
This is all noteworthy because it shows that more than half of the American Mormon population was completely unaware that their own church leaders had only a few decades ago taught that blacks were "less valiant" in their pre-earth life. In contrast, the messy details of Joseph Smith's polygamy and polyandry were not similarly taught in an official capacity by LDS church leaders throughout the 20th century. Thus, it is not unreasonable to suspect that the Church's recent revelations on the historical particulars of polygamy were very likely news to the vast majority of LDS Church members.
In my personal anecdotal experience, most of my Mormon friends and family members are, at best, only peripherally aware that these historical essays even exist and very few have actually taken the time to read them or reflect on their implications. While the LDS Church has, to its great credit, made this information available on its official website and has been making great strides recently toward more openness and transparency about its history, it has not yet been actively publicizing or promoting these developments to its members either in its educational curricula or semiannual discourses by Church leaders, the sources where most Mormons expect the "true" and "approved" version of their history to be taught. Until the LDS Church makes a more aggressive effort on this front, we should expect that most Mormons will continue to remain uninformed and "in the dark" about these important details from their own history.