Whether it is news headlines or WhatsApp messages, modern humans are inundated with short pieces of text. Now researchers say they have unpicked how we get their gist in a single glance.
Prof Liina Pylkkanen, co-author of the study from New York University, said most theories of language processing assume words are understood one by one, in sequence, before being combined to yield the meaning of the whole sentence.
“From this perspective, at-a-glance language processing really shouldn’t work since there’s just not enough time for all the sequential processing of words and their combination into a larger representation,” she said.
However, the research offers fresh insights, revealing we can detect certain sentence structures in as little as 125 milliseconds (ms) – a timeframe similar to the blink of an eye.
Pylkkanen 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.
“So just like your own car is quickly identifiable in a parking lot, certain language structures are quickly identifiable and can then give rise to a rapid effect of syntax in the brain.”
The team say the findings suggest parallels with the way in which we perceive visual scenes, with Pylkkanen noting the results could have practical uses for the designers of digital media, as well as advertisers and designers of road signs.
Writing in the journal Science Advances, Pylkkanen and colleagues report how they used a non-invasive scanning device to measure the brain activity of 36 participants.
Each participant was presented with a three-word starting sentence that flashed up for 300ms, followed by a second sentence that was either identical or differed by one word. Participants were asked to indicate whether the sentences matched, with the experiment repeated using different starting sentences.
The results reveal participants made faster and more accurate judgments on whether the sentences matched when they contained a subject, verb and object – such as “nurses clean wounds” – than when they contained a list of nouns such as “hearts lungs livers”.
What’s more, participants’ brain activity rapidly increased in response to a starting sentence with a subject, verb and object, with activity detected in the left-middle temporal cortex within 130ms – about 50ms quicker than for a list of nouns.
A similar rapid response was noted when starting sentences with a subject, verb and object were altered so that they contained an agreement error – for example “nurses cleans wounds” – or became implausible, for example “wounds clean nurses”.
But the effect disappeared when the sentences were given less typical structures, for example “wounds nurses clean” or “wounds cleans nurses”. Pylkkanen said that suggests these sequences do not trigger the same sentence-recognition system.
While the authors note they focused on English, adding that rapid at-a-glance comprehension may rely on other features in different languages, they say the study offers new insights.
“The earliest stage of at-a-glance comprehension appears to be more structure than meaning driven,” they write.
