Legal documents are famously hard to decipher. Even seasoned lawyers find themselves tripping over the dense, convoluted language also known as “legalese”. But why is legalese so difficult to understand? You might think it’s because laws need to be incredibly precise, leaving no detail unspecified but complicating language in the process. However, this is only part of the picture.

A team of cognitive scientists from MIT believes they have found the answer, and it might surprise you. According to the researchers, legal language is not merely a byproduct of historical tradition in law or necessity. It serves a deeper psychological purpose.

They argue that, much like the mystical language used in magic spells, legalese signals a unique kind of authority. In other words, the complexity of legal writing is quite intentional.

The Magic Spell Hypothesis

The researchers tested their hypothesis by asking 200 non-lawyers to write laws and stories about crimes. The participants naturally used convoluted structures when writing laws prohibiting crimes such as drunk driving, burglary, arson, and drug trafficking but opted for plain English in their fiction stories. This pattern held true even when participants were asked to revise their drafts, debunking another plausible theory that legalese results from repeated editing.

Instead, the study supports what the researchers call the “magic spell hypothesis.” Just as spells are distinguished by a unique style that sets them apart from everyday language, legalese seems to convey a similar sense of formality and power.

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

In a 2022 study, the same team of researchers examined 3.5 million words from legal contracts, comparing them with movie scripts, newspaper articles, and academic papers. Their analysis uncovered a common pattern in legal documents: lengthy definitions often interrupt sentences. This structure is known as “center-embedding.” And this type of construction, linguists have noted, significantly increases the difficulty of understanding the text.

“Legalese somehow has developed this tendency to put structures inside other structures, in a way which is not typical of human languages,” Gibson says.

In another series of experiments, around 80 participants were asked to draft laws and then write descriptions to explain those laws to visitors from another country. When crafting the laws, participants consistently used center-embedded structures. However, they avoided this complex phrasing when writing the explanations. This switching back and forth from complex to simpler language, points to the idea that legalese is more about signaling authority than giving clarity.

“In English culture, if you want to write something that’s a magic spell, people know that the way to do that is you put a lot of old-fashioned rhymes in there. We think maybe center-embedding is signaling legalese in the same way,” Gibson added.

A Historical Perspective

Gibson’s team is now looking deeper into the roots of legalese, investigating whether this complex language style has historical origins. Early American laws, heavily influenced by British law, may hold clues. The researchers even plan to analyze the Hammurabi Code, one of the earliest known sets of laws, to see if similar patterns exist.

“There may be just a stylistic way of writing from back then, and if it was seen as successful, people would use that style in other languages,” Gibson says. “I would guess that it’s an accidental property of how the laws were written the first time, but we don’t know that yet.”

The hope is that this research will inspire efforts to make legal language more accessible. Despite decades of calls for plainer legal writing, little has changed. A better understanding of what makes legalese so impenetrable could finally lead to meaningful reform.

The findings appeared in the journal Proceedings of the National Academy of Sciences.