The influence of concreteness on emotional nouns valence processing: An ERP study

Rapid responses to emotional words play a considerable role in human social communication. It has been reported that individuals have an advantage to process emotional words in comparison with neutral words. While it is crucial to distinguish between words that convey concrete concepts and abstract concepts in emotional words processing, because many studies have found that concrete words (e.g., "desk") are processed more quickly and efficiently than abstract words (e.g., " truth"), which is termed as the concreteness effects. However, much is known about the representation and processing of concrete concepts, our understanding of abstract concepts is limited, and the way in which abstract concepts are represented has received a great deal of research interest. Recent research has found an "abstractness effect", that is, a processing advantage of abstract words over concrete words, suggesting the role of affective information in the representation of abstract concepts. In the present study, we distinguished emotional nouns into concrete concepts and abstract concepts to explore potential differences in processing, as measured by event-related potentials. A dual-target RSVP task was employed to explore the processing stages of concrete and abstract nouns in the limited attention context. A total of 24 right-handed participants (8 males) aged from 18 to 30 years old took part in this study in exchange for payment. Brain electrical activity was recorded by a 64-channel system composing of tin electrodes mounted in an elastic cap according to the international 10-20 System. In addition to behavioral responses, P1, N170, and LPC components were selected as indicators of early and late processing stages of emotional nouns. The behavioral results showed that there was no concreteness effect or abstractness effect of emotional nouns in the context of limited attentional resources, while it reflected a "negative bias" for emotion effect. ERP results suggested N170 component was modulated by emotion valence and concreteness, that emotional nouns elicited significantly larger N170 amplitude than neutral nouns, and concrete nouns elicited significantly larger N170 amplitude than abstract nouns. Above two modulation patterns of N170 component were observed in the left hemisphere, but not in the right hemisphere. LPC component was also modulated by emotion valence and concreteness, that emotional nouns elicited significantly LPC amplitude than neutral nouns, while in contrast to previous studies, concrete nouns elicited significantly larger LPC amplitude than abstract nouns, which might reflect the attention resource allocation or the effect of emotional information on concreteness effect. Last but not least, there was an interaction effect between concreteness and emotion valence, that positive, negative, and neutral of abstract nouns could be distinguished by LPC amplitude respectively, while it could only differentiate emotional concrete nouns from non-emotional nouns. The late stage of emotional noun processing was in accordance with the abstractness effect. Emotion valence and concreteness both modulate the ERP components in the early and late stages of noun processing in the limited attention context. In the late processing stage, LPC amplitude distinguishing abstract nouns with different valence, which indicates that abstract nouns had more emotional valence than concrete nouns, and provides electrophysiological evidence for the view that abstract words contain more emotional information.