Age-related differences in animacy effects as a function of word-order canonicity in a verb-final language: Evidence from ERP

Objectives: Animacy is an important issue in the research of sentence processing, associated with thematic role assignment, grammatical relations and linear ordering of sentential constituents. Based on the animacy effects reported in previous research, the current study aimed to investigate whether the animacy effects are replicated in processing Korean sentences in which canonicity is manipulated in younger and elderly adults, using event-related potentials (ERPs). Methods: The ERP data from 34 adults (16 young and 18 elderly) were analyzed. Simple transitive sentences composed of 2 noun phrases, an adverb, and a verb were used as experimental stimuli and animacy was manipulated at the grammatical object position in canonical and non-canonical sentences. ERPs were recorded while the participants performed a sentence comprehension task. Results: For young adults, animate objects (NP2) in canonical sentences engendered greater N400 effects than inanimate objects, whereas inanimate objects (NP1) in non-canonical sentences induced greater N400 effects than animate objects. In the elderly group, there were no significant animacy effects for any of the critical words. Conclusion: The current study demonstrated that animacy effects on sentence processing are closely related to the linear ordering of arguments based on animacy hierarchy, and when these semantic expectancies are violated, processing costs could be raised. However, it seems that this animacy processing might be less efficient in the aging population.