Poster B58, Tuesday, August 20, 2019, 3:15 – 5:00 pm, Restaurant Hall
Neurophysiological evidence of the transformation of phonological into phonographic representations
Chotiga Pattamadilok1, Deirdre Bolger2, Anne-Sophie Dubarry1;1Aix Marseille Univ, CNRS, LPL, Aix-en-Provence, 2Aix Marseille Univ, Institute of Language, Communication and the Brain (ILCB), Aix-en-Provence
Studies on the influence of reading acquisition on speech processing have shown that acquiring an orthographic code changes the nature of speech representations. One important change that has been discussed in the literature is that the phonological representations are contaminated by spelling knowledge and transformed into “phonolographic” representations. Nevertheless, so far, no empirical evidence of such transformation has been reported. The present study addressed this issue using a combination of a new word learning protocol and EEG (electroencephalography) acquisition during an unattended oddball paradigm which elicited the Mismatch Negativity (MMN) component. Two groups of 16 native French speakers participated in the study that was conducted in two experimental sessions. During the first session, all participants learned the spoken and written forms of three new words, which all ended with the same phonological rime, i.e., /izo/, /ivo/, /iʒo/. For one group of participants, /izo/ and /ivo/ shared the same rime spelling, i.e., “izôt” and “ivôt”, while /iʒo/ had a different spelling, “ijaux”. For the other group of participants, the rime spellings of /ivo/, /iʒo/ were reversed yielding “ivaux” and “ijôt”. A letter detection task and a dictation task were conducted to ensure that the participants had correctly learned the spellings of the new words. Immediately after the learning phase, the auditory version of the new words were presented in an unattended oddball paradigm in which /izo/ represented the standard stimulus, and /ivo/ and /iʒo/ the rare-deviant stimuli, which were either orthographically congruent or incongruent with the rime spelling of /izo/. During the oddball paradigm, participants watched a silent movie while they were passively exposed to the spoken inputs. Their EEG activity was continuously recorded. The second session took place one week later. Participants only performed the oddball paradigm part of the study with EEG acquisition, without being exposed to the written forms of the new words. A dictation task was conducted again at the end of each EEG session. The data obtained in the two groups of participants were combined in order to eliminate any acoustic differences between the two deviant conditions. MMN responses generated by the deviant stimuli were calculated separately for the orthographically congruent and incongruent conditions and for the two sessions. In both sessions, typical MMNs were observed over fronto-central and central regions, reflecting automatic discrimination of standard and deviant stimuli. In the first EEG session, we found no evidence that the characteristics of the MMNs were modulated by the orthographic congruency between the standard and the deviant stimuli, thus suggesting that only the phonological representations played a role immediately after the learning phase. Most interestingly, the impact of orthography emerged in the second EEG session, with orthographic incongruity leading to an increase in MMN amplitude. The delayed emergence of the impact of orthographic knowledge reported here provides new evidence of an integration of phonological and orthographic information and, thus, the transformation of “phonological” to “phonographic” representations that occurs once newly acquired knowledge had been consolidated.
Themes: Perception: Speech Perception and Audiovisual Integration, Speech Perception
Method: Electrophysiology (MEG/EEG/ECOG)