Poster A31, Tuesday, August 20, 2019, 10:15 am – 12:00 pm, Restaurant Hall
Acquisition Of Concrete Vs. Abstract Semantics: ERP Evidence
Nadezhda Mkrtychian1, Daria Gnedykh1, Diana Kurmakaeva1, Evgeny Blagovechtchenski1, Svetlana Kostromina1, Yury Shtyrov1,2;1St. Petersburg State University, 2Aarhus University
The brain underpinnings of storage and processing of concrete vs. abstract semantics remain poorly understood. Whereas numerous studies have demonstrated the so-called «concreteness effect» – processing advantages for concrete over abstract semantics manifest in e.g. faster and more accurate behavioral responses – its neural origins are unclear. Here, we address this question by recording the brain’s EEG responses to novel concrete and abstract words in the process of their acquisition. Twenty novel Russian words with new concrete or abstract meanings, matched for length, bi- and tri-gram frequency, were presented to 20 healthy adult Russian speakers in context of sentences (5 per word) that helped reveal the new word meaning. To test the brain activity for the newly acquired words, high-density EEG was recorded in a passive reading block immediately after the learning session, which included novel words, their lexical competitors, matched control words and pseudowords, and infrequent target stimuli. Global Field Power analysis indicated three most prominent peaks at ~100 ms, 200 ms, and 332 ms after the stimulus onset. ERP amplitudes were extracted from 40-ms wide windows around these peaks and compared between conditions using rmANOVAs as well Wilcoxon signed rank test and cluster-based permutation statistics, with corrections for multiple comparisons. Behaviourally, both semantic types were acquired with similar efficiency. There were no significant differences between novel concrete and abstract words in behavioral results (reaction times and accuracy scores) for recall, lexical decision, and semantic definition tasks, although recognition task showed a faster response for abstract words than concrete. Crucially, the ERP analysis revealed significant effects at all main response peaks. The first time window showed more positive response to concrete concepts than abstract ones over central areas. There was also a generally reduced activity to concrete concepts compared to control pseudowords. The second peak exhibited reduced negativity in the right hemisphere for novel concrete concepts as opposed to both abstract concepts and control pseudowords. The most profound differences were observed in the third interval, which revealed more negative-going activity the central and prefrontal electrodes of both hemispheres in response to new abstract words in comparison to concrete ones. These results suggest neutrally more efficient contextual acquisition of concrete semantics specifically, leading to reduced ERP amplitudes, similar to what was shown previously for word vs. non-word comparisons. In the same time window, the comparison with untrained control pseudowords showed a more positive-going ERP in the central and prefrontal areas for the new concrete concepts, whereas no such difference was found between the new abstract concepts and control pseudowords in any of the intervals. Thus, despite the overall similar behavioural efficiency of controlled contextual acquisition of concrete and abstract semantics, the underpinning brain activation diverged, suggesting distinct brain mechanisms of their processing. Crucially, while novel concrete items exhibited different ERP patterns from unfamiliar pseudowords suggesting their successful integration into the neural lexicon, the new abstract words did not show this pattern, indicating the advantage of concrete over abstract semantics at the neural level. Supported by RF Government grant contract No.14.W03.31.0010.
Themes: Meaning: Lexical Semantics, Methods
Method: Electrophysiology (MEG/EEG/ECOG)