How brain detects grammatical error even when you are unaware

Tuesday, 14 May 2013 - 12:28pm IST | Place: Washington, DC | Agency: ANI
This non-invasive technique allows for the capture of changes in brain electrical activity during an event.

A study has shown that our brain often works on autopilot when it comes to grammar.

That theory has been around for years, but University of Oregon neuroscientists have captured elusive hard evidenc.e that people indeed detect and process grammatical errors with no awareness of doing so.

Participants in the study -- native-English speaking people, ages 18-30 –- had their brain activity recorded using electroencephalography, from which researchers focused on a signal known as the Event-Related Potential (ERP).

This non-invasive technique allows for the capture of changes in brain electrical activity during an event.

In this case, events were short sentences presented visually one word at a time.

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.”

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

This approach, lead author Laura Batterink, a postdoctoral researcher said provided a signature of whether awareness was at work during processing of the errors.

When tones appeared after grammatical errors, subjects detected 89 percent of the errors.

In cases where subjects correctly declared errors in sentences, the researchers found a P600 effect, an ERP response in which the error is recognized and corrected on the fly to make sense of the sentence.

When the tones appear before the grammatical errors, subjects detected only 51 percent of them.

The tone before the event, said co-author Helen J. Neville, who holds the UO’s Robert and Beverly Lewis Endowed Chair in psychology, created a blink in their attention.

The key to conscious awareness, she said, is based on whether or not a person can declare an error, and the tones disrupted participants’ ability to declare the errors.

But, even when the participants did not notice these errors, their brains responded to them, generating an early negative ERP response.

These undetected errors also delayed participants’ reaction times to the tones.

The study is published in the Journal of Neuroscience.


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