McGraw Hill swiftly did its damage control. It announced that it was changing the caption in both the digital and print versions to characterize the migration accurately as a “forced” diaspora of slaves: “We conducted a close review of the content and agree that our language in that caption did not adequately convey that Africans were both forced into migration and to labor against their will as slaves,” the company said in a statement. “We believe we can do better.” Catherine Mathis, the company’s spokeswoman, also emphasized that the textbook accurately referred to the slave trade and its brutality in more than a dozen other instances. And McGraw Hill has offered to provide various additional resources to any school that requests them, including supplemental materials on cultural competency, replacement textbooks, or stickers with a corrected caption to place over the erroneous one. But Texas school districts were already in possession of more than 100,000 copies of the book, while another 40,000, according to Mathis, are in schools in other states across the country.

If nothing else, the incident may serve as yet another example of why social studies—and history in particular—is such a tricky subject to teach, at least via textbooks and multiple-choice tests. Its topics are inherently subjective, impossible to distill into paragraphs jammed with facts and figures alone. As the historian and sociologist Jim Loewen recently told me, in history class students typically “have to memorize what we might call ‘twigs.’ We’re not teaching the forest—we’re not even teaching the trees,” said Loewen, best known for his 1995 book Lies My Teacher Told Me: Everything Your American History Textbook Got Wrong. “We are teaching twig history.”

This is in part why a growing number of educators are calling for a fundamental shift in how the subject is taught. Some are even calling on their colleagues to abandon traditional models of teaching history altogether. Instead of promoting the rote memorization of information outlined in a single, mass-produced textbook, these critics argue that teachers should use a variety of primary-source materials and other writings, encouraging kids to analyze how these narratives are written and recognize the ways in which inherent biases shape conventional instructional materials. In an essay for The Atlantic earlier this year, Michael Conway argued that history classes should focus on teaching children “historiography”—the methodologies employed by historians and the exploration of history itself as an academic discipline:

Currently, most students learn history as a set narrative—a process that reinforces the mistaken idea that the past can be synthesized into a single, standardized chronicle of several hundred pages. This teaching pretends that there is a uniform collective story, which is akin to saying everyone remembers events the same. Yet, history is anything but agreeable. It is not a collection of facts deemed to be “official” by scholars on high. It is a collection of historians exchanging different, often conflicting analyses. And rather than vainly seeking to transcend the inevitable clash of memories, American students would be better served by descending into the bog of conflict and learning the many "histories" that compose the American national story.

But according to Loewen, the shortcomings of the country’s history teachers make the improvement of its instruction, let alone the introduction of historiography, a particularly difficult feat. Compared to their counterparts in other subjects, high-school history teachers are, at least in terms of academic credentials, among the least qualified. A report by the American Academy of Arts & Sciences on public high-school educators in 11 subjects found that in the 2011-12 school year, more than a third—34 percent—of those teaching history classes as a primary assignment had neither majored nor been certified in the subject; only about a fourth of them had both credentials. (At least half of the teachers in each of the other 10 categories had both majored and been certified in their assigned subjects.)