Investigating the Electrophysical Correlates of Language Processing Regarding Age of Acquisition and Emotion

Abstract

The emotional characteristics of written words is well known to effect how they are processed. It is also well known that how early in life words are learnt (i.e., their age of acquisition - AOA) also effects how they are processed with early AOA words being processed more efficiently than late AOA words. However, the impact of this phenomenon on the processing of written emotional words has not been studied. Using event-related potentials, this effect was investigated on the processing of such words. The results showed a strong and sustained effect of AOA effect from very early in processing (100 ms). Alternatively, there was no effect of early posterior negativity around 250 ms, which has been suggested to be a marker of early attentional capture of emotionally arousing words. The effect AOA produced at this time had a similar topography as early posterior negativity, suggesting that this may have been a potential confound in previous studies. The results also showed that emotional status interacted with AOA on the N400, a well-known marker of semantic processing, where emotional words showed an effect of AOA, but emotionally neutral control words did not. This suggests that the way semantic is learnt in affective words differs depending on their AOA. Further analyses examining the effect of AOA on alpha desynchronization found that late AOA words caused more desynchronization than early AOA words suggesting they are more difficult to process. However, the lack of an interaction with emotional status suggests that emotion causes qualitatively differences in processing, rather than simpler more-or-less processing. Keywords: Age of Acquisition, Emotion, Language Development, EEG