A rather debatable theory in psychology says  the brain detects grammar errors even when we don’t consciously pay attention to them, sort of working on autopilot. Now, researchers at University of Oregon have come with  tangible evidence pointing toward this idea after they performed a brain scan study.

The team of psychologists, led by Laura Batterink, a postdoctoral researcher, invited native-English speaking people, ages 18-30, to read out various sentences, some of which  containing grammatical errors, and signal whether these were correct or not. During the whole task, the participants had their brain activity recorded using electroencephalography, from which researchers focused on a signal known as the Event-Related Potential (ERP).

Subjects were given 280 experimental sentences, including some that were syntactically (grammatically) correct and others containing grammatical errors, such as “We drank Lisa’s brandy by the fire in the lobby,” or “We drank Lisa’s by brandy the fire in the lobby.”  In order to create a distraction and make participants less aware, a 50 millisecond audio tone was also played at some point in each sentence. A tone appeared before or after a grammatical faux pas was presented. The auditory distraction also appeared in grammatically correct sentences.

 “Participants had to respond to the tone as quickly as they could, indicating if its pitch was low, medium or high,” Batterink said. “The grammatical violations were fully visible to participants, but because they had to complete this extra task, they were often not consciously aware of the violations. They would read the sentence and have to indicate if it was correct or incorrect. If the tone was played immediately before the grammatical violation, they were more likely to say the sentence was correct even it wasn’t.”

Your brain: a grammar nazi

The researchers found that when the tones appeared after grammatical errors, subjects detected 89 percent of the errors, but when the tones appear before the grammatical errors, subjects detected only 51 percent of them. It’s clear the tone created a disruption in the participants’ attention. Even so, while the participants weren’t able to be consciously aware of the grammar errors, their brains picked up the errors generating an early negative ERP response. These undetected errors also delayed participants’ reaction times to the tones.

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“Even when you don’t pick up on a syntactic error your brain is still picking up on it,” Batterink said. “There is a brain mechanism recognizing it and reacting to it, processing it unconsciously so you understand it properly.”

“While other aspects of language, such as semantics and phonology, can also be processed implicitly, the present data represent the first direct evidence that implicit mechanisms also play a role in the processing of syntax, the core computational component of language.”

These findings might warrant changes in the way adults learn new languages. Children, for instance, learn to speak a language, and conversely pick up its grammar structure, simply  routine daily interactions with parents or peers, simply hearing and processing new words and their usage before any formal instruction.

“Teach grammatical rules implicitly, without any semantics at all, like with jabberwocky. Get them to listen to jabberwocky, like a child does,” said Neville, referring  to “Jabberwocky,” the nonsense poem introduced by writer Lewis Carroll in 1871 in “Through the Looking Glass,” where Alice discovers a book in an unrecognizable language that turns out to be written inversely and readable in a mirror.

The findings were detailed in the  Journal of Neuroscience.