In a 2005 study, Mariana Achugar of Carnegie Mellon University and Mary J. Schleppegrell of the University of Michigan set out to examine how language shapes knowledge in history. Specifically, the authors looked at how the language used in history textbooks influenced the study of causality, that is, the link between particular actions and specific outcomes. They discovered that certain texts that set out to explain cause and effect contained wording that might prevent students from understanding this important concept.

The researchers focused on two historical accounts. One, from an eighth-grade textbook, concerned the expulsion of the Cherokee from Georgia. The other discussed causes of the Great Depression and came from a tenth-grade textbook. Since the writing in both was typical of middle and high school texts, Achugar and Schleppegrell looked for linguistic patterns that might help students draw a connection between cause and effect.

First, they identified two kinds of passages: accounts and explanations. An account was defined as a chronological narrative in which cause and effect emerge as a natural sequence of events, while an explanation frames events in an organized way, highlighting the key factors students should focus on.

To their surprise, the researchers found that the language in the explanatory passage (the one about the Great Depression) was no more help in explaining causality to students than the account about the Cherokee. While the "explanation" was organized differently, it suffered from the same problems that plagued the "account" of the Cherokees' removal. Both texts relied heavily on abstract nouns, failed to use explicit language linking cause and effect, and frequently employed the passive voice in describing events. Consequently, both passages created the impression that the course of history was somehow inevitable. Language, it seems, matters a great deal in shaping ideas about causality.

In the passage on Cherokee removal, the text constantly resorted to abstractions: It referenced Cherokee "resistance" without exploring what that resistance looked like or why it was unsuccessful. While the Great Depression text did focus on causes, it too used overly abstract language. Phrases like "economic overproduction" and "lessening demand" held little meaning for students trying to connect certain actions with specific actors.

As the researchers explained, rhetorical connectors, such as the word "because," can help students draw a direct link between cause and effect. Unfortunately, few of these connectors appeared in either text. They focused on "what happened," but stopped short of establishing the causal relationships that would help students understand why these events took place.

In each text, the use of the passive voice (a less direct, bold, or concise form of expression using wordy phrases like "it could be," "there were times that," "it was said," etc.) creates the appearance that events in question were inevitable. The eighth-grade text relates how the Cherokee were expelled from their land by the Georgia State Militia, but never identifies motives for ordering the tribe's removal. Similarly, in the high school passage on the Great Depression, the passive voice creates the impression that things were bound to turn out the way they did. The text cites an "uneven distribution of wealth," but never explores how or why that was the case.