A recent study published in The American Statistician highlights the intricate family connections among African Americans, suggesting that calling someone a “cousin” may often reflect genuine kinship rather than just an affectionate term. This research, conducted by a team at Stanford University, employs a mathematical model to explore ancestry within the context of American slavery, revealing significant ties that span centuries.
The study indicates that for two randomly selected African Americans born between 1960 and 1965, there is a 19% to 31% chance they share at least one ancestor who was forcibly brought to North America during the Transatlantic Slave Trade. This percentage increases dramatically for those born between 1985 and 1990, where the likelihood of sharing an ancestor rises to over 50%, essentially equating to a coin flip.
Understanding the Mathematical Approach
Led by Noah Rosenberg, a professor of biology at Stanford, the research utilizes a statistical concept known as the “birthday problem” to analyze genealogical connections. This classic problem illustrates how, with a limited number of outcomes—in this case, days in a year—there is a statistically significant chance that individuals will share common characteristics, such as birthdays. Rosenberg and his colleagues adapted this principle to assess shared ancestry among individuals whose predecessors endured the same historical circumstances.
The researchers estimated that African Americans born in the early 1960s have approximately 300 ancestors among the estimated 400,000 to 500,000 Africans transported to North America from the early 1600s to 1860. By examining the overlap in these ancestral lines, the study underscores the interconnectedness of African American families across generations.
Filling Historical Gaps in Ancestry
Previous studies have employed genetic methods to explore African American ancestry, but this research aims to provide insights that transcend individual genetic links. While it does not establish direct connections between specific descendants and ancestors, Rosenberg emphasizes the importance of mathematical modeling in uncovering shared heritage.
“In most cases, the question of whether two specific people have a shared transported ancestor cannot be directly answered because many aspects of the history of slavery led to profound loss of genealogical information,” Rosenberg explained. “A mathematical model therefore has potential to make a meaningful contribution.”
This research contributes to a growing body of work aimed at bridging the gaps in knowledge surrounding African American ancestry, a topic often complicated by the historical context of slavery and inadequate record-keeping. By leveraging mathematical approaches, the team seeks to illuminate the complexities of lineage and heritage, offering a more comprehensive understanding of familial connections within the African American community.
As this study demonstrates, the interplay between mathematics and genealogy can reveal significant insights about the past, reflecting a shared history that continues to affect the present.
