Date Published: March 28, 2018
Publisher: Public Library of Science
Author(s): Simritpal Kaur Malhi, Lori Buchanan, Francesco Di Russo.
In Experiment 1, the symbol interdependency hypothesis was tested with both concrete and abstract stimuli. Symbolic (i.e., semantic neighbourhood distance) and embodied (i.e., iconicity) factors were manipulated in two tasks—one that tapped symbolic relations (i.e., semantic relatedness judgment) and another that tapped embodied relations (i.e., iconicity judgment). Results supported the symbol interdependency hypothesis in that the symbolic factor was recruited for the semantic relatedness task and the embodied factor was recruited for the iconicity task. Across tasks, and especially in the iconicity task, abstract stimuli resulted in shorter RTs. This finding was in contrast to the concreteness effect where concrete words result in shorter RTs. Experiment 2 followed up on this finding by replicating the iconicity task from Experiment 1 in an ERP paradigm. Behavioural results continued to show a reverse concreteness effect with shorter RTs for abstract stimuli. However, ERP results paralleled the N400 and anterior N700 concreteness effects found in the literature, with more negative amplitudes for concrete stimuli.
Understanding the mechanism through which humans obtain meaning from words has been an ongoing pursuit for researchers in the area of psycholinguistics. Over the years, various theories have been proposed to explain how we understand words in general and how we understand concrete versus abstract words. A review of these theories and their associated empirical findings follows (see Table 1 for a summary). This will set the stage for the present study which will test the symbol interdependency hypothesis using a stimulus set that taps into concrete and abstract relationships in a novel way.
The present investigation was a two-part study with Experiment 1 testing the symbol interdependency hypothesis with both concrete and abstract stimuli (and a novel symbolic factor, i.e., semantic neighbours from WINDSORS) and Experiment 2 following up on an abstractness finding using ERPs. The stimulus set developed for the present study activated the relationship between the word pairs as opposed to activation at the level of the individual words—this removed the confound of concretizing abstract words. The results of Experiment 1 supported the symbol interdependency hypothesis. The symbolic factor (i.e., semantic neighbourhood distance) was recruited for the task tapping symbolic relations (i.e., semantic relatedness task) and the embodied factor (i.e., iconicity) was recruited for the task tapping embodied relations (i.e., iconicity task). Across tasks, and especially for the iconicity task, abstract word pairs had shorter RTs compared to concrete word pairs. We proposed a time-costly (two-steps) visualization approach in the iconicity task for concrete word pairs and a time-efficient (one step) emotional valence approach for abstract word pairs. Experiment 2 replicated the iconicity task in an ERP study and found greater N400 and N700 (an index of imagery) amplitudes for the concrete word pairs compared to the abstract word pairs, supporting the proposal that participants were taking a visualization approach to the concrete word pairs.