Researchers first studied the pattern in the children of Holocaust survivors. In the 1980s, Lakota social worker Maria Yellow Horse Brave Heart developed the concept of historical trauma to describe the collective wounds of Native peoples from massacres, land theft and boarding schools. A 2024 US Interior Department report identified 417 federal Indian boarding schools and at least 973 children who died while attending them.
For Black Americans, psychologist Joy DeGruy described the lasting effects of slavery and racism in her 2005 book "Post Traumatic Slave Syndrome." Trauma is not only a memory passed down. It is renewed by present-day conditions such as police violence, segregation and wealth gaps that grew out of the same history.
Some scientists study whether trauma leaves biological marks that pass to children, but that research is still debated. The broader point is not in dispute: the damage of systemic violence does not end with the people who first experienced it.