A compositional neural code in high-level visual cortex can explain jumbled word reading.

Aakash Agrawal,Kvs Hari,S P Arun

doi:10.7554/elife.54846

Abstract

We read jubmled wrods effortlessly, but the neural correlates of this remarkable ability remain poorly understood. We hypothesized that viewing a jumbled word activates a visual representation that is compared to known words. To test this hypothesis, we devised a purely visual model in which neurons tuned to letter shape respond to longer strings in a compositional manner by linearly summing letter responses. We found that dissimilarities between letter strings in this model can explain human performance on visual search, and responses to jumbled words in word reading tasks. Brain imaging revealed that viewing a string activates this letter-based code in the lateral occipital (LO) region and that subsequent comparisons to stored words are consistent with activations of the visual word form area (VWFA). Thus, a compositional neural code potentially contributes to efficient reading.

Highlights

Reading is a recent cultural invention, yet we are remarkably efficient at reading words and even jmulbed wrods (Figure 1A)
In Experiments 2–4, we show that search for longer strings can be predicted using these artificial neurons with a simple compositional rule
We investigated whether jumbled word reading can be explained using a purely visual representation

Summary

Introduction

Reading is a recent cultural invention, yet we are remarkably efficient at reading words and even jmulbed wrods (Figure 1A). It is easier to read frequent words, words with frequent bigrams or trigrams as well as shuffled words that preserve intermediate units such as consonant clusters or morphemes (Norris, 2013; Grainger, 2018). Despite these insights, it is not clear how these factors combine, what their distinct contributions are, and more generally, how word representations relate to letter representations

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Conclusion