Our brains can process full sentences in split-seconds, just like we see photos, says study

New York

The human brain can process some sentence structures in as little as 125 milliseconds, a power that scientists did not know existed till now, dispelling the notion that we decipher sentences word by word.

Earlier theories have suggested that human brains process sentences by understanding the meaning of each word.

The recent study by New York University researchers led by Prof Liina Pylkkanen found that the participants were able to recognise familiar grammatical structures, similar to visual recognition, as in, how we identify our cars in parking lots.

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To uncover this hitherto unknown brain power, the scientists studied 36 participants using a non-invasive brain scanning device.

They were shown brief sentences and were able to quickly and accurately understand those that had the standard subject-verb-object sequences.

First, a three-word starting sentence was flashed for 300 milliseconds, then a similar sentence, with one different word or order.

They were asked to indicate whether the sentences were identical.

The study found higher brain activity in the left-middle temporal cortex of the brains within 130 milliseconds when grammatically standard sentences were shown. 

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Comprehending lists that contained nouns, however, took a longer time, with activity in the left-middle temporal cortex 50ms slower.

Curiously enough, sentences were recognised faster even when they had grammar errors, or were implausible.

The researchers concluded that faster comprehension happens when one is familiar with sentence structures rather than meaning.

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Published in Science Advances, the research findings show that at-a-glance language processing may have parallels with visual perception. In other words, we can 'see' whole sentences just like pictures, and comprehend their meaning without having to go through words sequentially. 

The research was done in the English language. But similar dynamics may exist for other languages with their unique grammatical features, posit the researchers.

Prof Liina Pylkkanen, co-author of the study from New York University, said, “We don’t yet know exactly how this ultrafast structure detection is possible.

"But the general hypothesis is that when something you perceive fits really well with what you know about – in this case, we’re talking about knowledge of the grammar – this top-down knowledge can help you identify the stimulus really fast," The Guardian quoted her as saying.

(With inputs from agencies)