Learning to read transforms phonological into phonographic representations.

Area of Science:

• Cognitive Neuroscience
• Psycholinguistics
• Speech Perception

Background:

• Reading acquisition significantly alters how the brain processes spoken language.
• The transformation of phonological (sound-based) to phonographic (print-based) speech representations is hypothesized but lacks direct evidence.
• Existing research has not fully elucidated the neurophysiological basis of this phonological-orthographic integration.

Purpose of the Study:

• To investigate the neurophysiological evidence for the emergence of phonographic representations following new word learning.
• To examine the temporal dynamics of orthographic influence on auditory speech perception.
• To determine if consolidated knowledge of written words affects the processing of their spoken forms.

Main Methods:

• A novel word learning paradigm where participants learned spoken and written forms of new words.
• Auditory perception of novel words was assessed using an unattended oddball paradigm.
• High-density electroencephalography (EEG) measured the Mismatch Negativity (MMN) component at immediate and delayed (one week) time points.

Main Results:

• No immediate effect of spelling knowledge on spoken word perception was observed post-learning.
• One week later, significant differences in Mismatch Negativity emerged, indicating enhanced discrimination between spoken words with different spellings.
• Similar sounding words with distinct spellings were perceived as more different than those sharing identical spellings.

Conclusions:

• Newly acquired orthographic knowledge influences auditory speech perception after a consolidation period.
• This study provides neurophysiological evidence for the integration of phonological and orthographic information, forming 'phonographic' representations.
• These findings suggest a mechanism for how literate individuals store and access known words in their mental lexicon.