The Brain and Language: How We Process a Sentence in the Blink of an Eye

Language Processing: Serial vs. Parallel

The brain has two main ways of processing language, depending on the mode of input:

1. Serial Processing: In spoken language, words are perceived sequentially, one after another. This method takes time to assemble the complete meaning.

2. Parallel Processing: In written language, the brain simultaneously analyzes the entire structure of a sentence, processing all the words at once. This method is similar to how it processes visual scenes.
   

The Experiment: Understanding Sentences in 300 Milliseconds

To study this phenomenon, researchers used magnetoencephalography (MEG) to measure brain activity as participants read short sentences like:

• "Dogs eat tacos"

• "Tacos dogs eat"
  

These sentences were displayed on a screen for 300 milliseconds, just enough time for the brain to process the stimulus without requiring eye movements.

Findings: The Importance of Syntax

The study found that the left temporal cortex begins constructing the grammatical structure of a sentence just 125 milliseconds after it appears. This demonstrates that the ability to quickly understand full sentences depends on syntax, or the grammatical order of words.

When the words were scrambled, participants took longer to recognize them and made more errors. This suggests that the brain relies on prior knowledge of language structure to process and quickly comprehend the meaning of a sentence presented in parallel.

An Analogy to Understand It Better

Imagine closing your eyes and placing your hand on an object, feeling it with your entire palm simultaneously. This approach allows you to identify it quickly because you perceive all its parts at once. Similarly, when the brain reads a written sentence, it can instantly understand it by "feeling" its entire structure in a single glance.

Conclusion

This study highlights the incredible ability of the human brain to efficiently process linguistic information. While spoken language relies on sequential processing, written language leverages a parallel approach that enables faster comprehension when syntactic structures are intact.

These findings not only deepen our understanding of the neuroscience of language but also open new possibilities for exploring how the brain organizes information in an amodal manner, regardless of the input modality.

Reference: Fallon, J., & Pylkkänen, L. (2024). Language at a glance: How our brains grasp linguistic structure from parallel visual input. Science Advances, 10(43), eadr9951. https://doi.org/10.1126/sciadv.adr9951