Morphemes as letter chunks: Linguistic information enhances the learning of visual regularities

We have previously shown that readers use co-occurrence statistics to learn about the presence and position of affix-like chunks in strings of pseudo-letters (Lelonkiewicz, Ktori & Crepaldi, 2020). These findings were taken as evidence that visual statistical learning might be implicated in morphological processing during visual word recognition. The present study seeks to specify this claim by (a) establishing the visual, language-agnostic nature of the underlying learning mechanism and (b) examining it in the presence of higher-order linguistic information. In Experiments 1a and 1b, readers were familiarized with strings of abstract shapes that involved affix-like chunks of frequently co-occurring shapes. We found that readers were sensitive to the presence and position of chunks. Further experiments revealed that presence and position effects were stronger when readers were exposed to letter strings which allowed access to orthographic and phonological representations (Experiments 2a and 2b), and were enhanced by access to semantics (Experiment 3). Our study demonstrates that the learning of visual regularities supports chunk identification both in purely visual and language-like materials, and that the availability of linguistic information enhances this learning.