Social hierarchy modulates Who Does Whom: ERP evidence from Chinese sentence processing

Social hierarchy as a social ranking system is conveyed verbally, nonverbally, or conjointly in communication. From a linguistic perspective, hierarchy concept is encoded via words, hierarchical or non-hierarchical when it is embedded in different contexts. However, few studies have explored how hierarchy is represented in the mental lexicon and processed neurocognitively. Backgrounded by this situation, we conducted two ERP experiments to investigate whether social hierarchy can be subcategorized into implicit and explicit forms and whether a word’s social hierarchy is processed similarly to its semantic knowledge relating to Who Does Whom neurologically. Experiment 1 compared the processing of three types of Chinese verbs with different degree of hierarchy (strong hierarchical verbs; weak hierarchical verbs; non-hierarchical verbs) in SVO sentences. Experiment 2 examined whether the dichotomy of hierarchical verbs was modulated by context type (neutral context or biased context) in processing. The results revealed three major findings: First, strong hierarchical verbs relative to non-hierarchical verbs elicited greater posterior-P600 at the verb and AN at the noun position; Second, weak hierarchical verbs relative to strong hierarchical verbs elicited enhanced AN and posterior-P600 effects at the verb and noun positions, while as compared to non-hierarchical verbs, weak hierarchical verbs elicited stronger P600 and AN effect at the verb and noun positions, respectively; Third, this hierarchy difference was much affected by context type. Specifically, in biased contexts, weak hierarchical verbs and strong hierarchical verbs became indistinguishable, while in neutral contexts, strong hierarchical verbs sentences were harder to process than weak hierarchical verbs, as indicated by the larger P600 effect at the verb position. These findings converge to suggest a unique neurocognitive mechanism underlying the processing of Chinese social hierarchy verbs and highlight the concept that a word’s social hierarchy is distinct from its lexical semantics. This study provides insights into how social hierarchy is decoded in language comprehension and offers implications for future research on linguistic structures and social cognition.