Determining the time course of lexical frequency and age of acquisition using ERP

The main goal of the present study was to dissociate the effects on reading of frequency, age of acquisition (AoA) and imageability using the evoked response potential paradigm.

Twenty participants read words from three experimental conditions: high and low frequency, late and early age of acquisition and high and low imageability.

High frequency words produced more positive mean amplitude than low frequency words in the 175-360 ms post-stimulus onset time window and late AoA produced more negative amplitudes than early AoA in the 400-610 ms window. Imageability did not produce any effect in any time window tested. Brain electromagnetic tomography showed the most activated cortical areas for each category of stimuli.

The lexical frequency of words seems to affect an early phase in the recognition process, perhaps at the level of the orthographic input lexicon, while AoA was observed at a later stage, indicating that this variable influence processing at a semantic level or at the links between semantics and phonology.

EEG permits the researcher to investigate the time course, and approximate location in the brain, of psycholinguistic variables.