MIT study explains why laws are written in an incomprehensible style | MIT News

Legal documents are notoriously difficult to understand, even for lawyers. This raises the question: why are these documents written in a style that makes them so incomprehensible?

MIT cognitive scientists believe they have found the answer to that question. Just as “magic spells” use special rhymes and archaic terms to signal their power, the convoluted language of legal jargon serves to convey a sense of authority, they conclude.

In a study published this week in the Journal of the Proceedings of the National Academy of SciencesThe researchers found that even non-lawyers use this type of language when tasked with drafting laws.

“People seem to understand that there is an implicit rule that laws should sound this way and that way, and they write them that way,” says Edward Gibson, a professor of brain and cognitive sciences at MIT and lead author of the study.

The lead author of the study is Eric Martinez PhD ’24. Francis Mollica, a lecturer at the University of Melbourne, is also an author of the article.

Casting a legal spell

Gibson’s research group has been studying the unique characteristics of legal jargon since 2020, when Martinez came to MIT after studying law at Harvard Law School. In a 2022 study, Gibson, Martinez and Mollica analyzed legal contracts totaling about 3.5 million words and compared them to other types of text, including screenplays, newspaper articles and academic papers.

This analysis revealed that legal documents often contain long definitions in the middle of sentences – a property known as “center embedding.” Linguists have previously found that this type of structure can make texts significantly more difficult to understand.

“There has somehow developed a tendency in legal language to insert structures into other structures in a way that is not typical of human languages,” says Gibson.

In a follow-up study published in 2023, researchers found that legalese also made documents more difficult for lawyers to understand. Lawyers tended to prefer plain English versions of documents and rated those versions as just as enforceable as traditional legal documents.

“Lawyers also find legalese unwieldy and complicated,” says Gibson. “Lawyers don’t like it, laypeople don’t like it, so the point of this article was to find out why they write documents this way.”

The researchers had several hypotheses as to why legalese is so widespread. One of them was the “copy-and-edit hypothesis,” which states that legal documents begin with a simple premise and then additional information and definitions are inserted into pre-existing sentences, creating complex, centrally embedded clauses.

“We thought it would be plausible to start with a simple first draft and then later think about all the other terms you want to include. And the idea is that once you get started, it’s much easier to embed that into the existing provision,” says Martinez, who is now a fellow and lecturer at the University of Chicago Law School.

But the results ultimately pointed to a different hypothesis, the so-called “spell hypothesis.” Just as spells are written in a distinctive style that sets them apart from everyday language, the convoluted style of legal language seems to signal a special kind of authority, the researchers say.

“In English culture, if you want to write a magic spell, you know you have to put in a lot of old-fashioned rhymes. We think that putting it in the middle might signal legalese in the same way,” says Gibson.

In this study, researchers asked about 200 nonlawyers (native English speakers living in the United States, recruited through a crowdsourcing site called Prolific) to write two types of texts. In the first task, participants were asked to write laws prohibiting crimes such as drunk driving, burglary, arson, and drug trafficking. In the second task, they were asked to write stories about these crimes.

To test the copying and editing hypothesis, half of the participants were asked to add additional information after writing their original law or story. The researchers found that all subjects wrote laws with centrally embedded subordinate clauses, regardless of whether they wrote the law all at once or if they were told to write a draft and add to it later. And when they wrote stories related to those laws, they wrote in much simpler English, regardless of whether they had to add information later.

“When they were writing legislation, they used a lot of center embedding, whether they had to edit the law or write it from scratch. And in this narrative text, they didn’t use center embedding in either case,” Martinez says.

In another set of experiments, about 80 participants were asked to write laws as well as descriptions that would explain those laws to visitors from another country. In these experiments, participants again used center embedding for their laws, but not for the descriptions of those laws.

The origins of legal jargon

Gibson’s lab is currently studying the origins of center embedding in legal documents. Early American laws were based on British law, so the researchers plan to analyze British laws to see if they exhibit the same type of grammatical construction. And going much further back, they plan to analyze whether center embedding can be found in the Code of Hammurabi, the oldest known legal code, which dates to around 1750 BCE.

“Perhaps there is simply a stylistic way of writing from that time, and if it was considered successful, people used that style in other languages ​​as well,” says Gibson. “I would suspect that it is a random property of the original spelling of the laws, but we don’t know that yet.”

The researchers hope that their work, which has identified certain aspects of legal language that make it harder to understand, will motivate lawmakers to make laws more understandable. Efforts to write legal documents in simpler language date back at least to the 1970s, when President Richard Nixon declared that federal laws should be written in “layman’s language.” Since then, however, legal language has changed little.

“We’ve only recently learned what makes legal language so complicated, and that’s why I’m optimistic we can change that,” Gibson says.