What Eye Movement Reveals Concerning Age-Related Dissociation in Syntactic Prediction: Evidence from a Verb-Final Language

By prof. Jee Eun Sung,
Department of Communication Disorders
Research Profile
jeesung@ewha.ac.kr

A research team led by Dr. Jee Eun Sung has been publishing a series of evidence on the aging-related decline in sentence processing from older adults using a verb-final language. Along with the line of research on aging and linguistic-cognitive decline, Dr. Sung published the following paper in a very prestigious journal, which is most widely read and cited by Speech-Language Pathologists in the field of communication sciences and disorders: "What Eye Movement Reveals Concerning Age-Related Dissociation in Syntactic Prediction: Evidence from a Verb-Final Language".

Linguistic changes in normal aging are multifaceted in nature. Older adults' increased linguistic experience is expected to accumulate semantic knowledge with increasing vocabulary and improved language expertise. On the other hand, their cognitive decline disrupts language processing leading to age-related degeneration in some domains of language, such as sentence comprehension.

How do older adults construct a sentential representation? Age-related changes in predictive processing during the online construction of a sentential representation have been a topic of controversial debate.

This study investigated how older adults implement predictive processing and construct sentential representations during auditory active and passive sentence processing in a verb-final language using the visual world eye-tracking paradigm. Verb-final languages could provide novel evidence for predictive processing. In verb-final languages, thematic assignment or structural analysis of the arguments is processed predictively before the verb onset because the verb is retained at the sentence end. This study used Korean active and passive sentences to investigate how older adults engage in predictive processing and construct a sentential representation. Korean is a head-final language with an elaborate case marking system to denote a grammatical relation and a thematic role of each noun phrase (NP).

This study employed the visual world eye-tracking paradigm to explore how older adults engage in predictive processing and construct a sentential representation compared to young adults. The paradigm is used to examine participants’ eye movement while they simultaneously observe a visual display and listen to an utterance. Eye movements are known to be a sensitive index to assess sentence-level processing. To our knowledge, no previous studies have explored the aging effects on verb-final sentence processing using the visual world eye-tracking paradigm, despite the potential contributions of both the verb-final structure and this paradigm in revealing age-related changes in predictive processing.

This study demonstrated that older adults showed qualitative differences in online sentence processing patterns compared to young adults, relying more strongly on predictive processing based on probabilistic information denoted by case markers. These results provide convincing evidence that aging could affect the manner of constructing a sentential representation during incremental sentence processing. Older adults’ reduced processing capacity engenders predictive processing patterns toward a simple and preferred representation. This becomes a smart choice when their prediction conforms to the input, but risky when it does not. Although the probability of reprocessing increases in the latter case, eliciting additional processing costs, older adults seem to take this burden, relying more on predictions based on probabilistic information. This propensity could be a driving force for older adults’ success in managing everyday communication despite their decreased processing capacity because everyday communication mostly occurs in a probabilistic fashion.

This study contributes to understanding how older adults build sentential representations by making use of the information of morphosyntactic cues in a verb-final language. These age-related changes in online sentence processing seem to be an adaptive response to age-related changes in processing capacity. To reduce the processing demands for linguistic computation and increase processing efficiency, older adults seem to more strongly rely on their accumulated linguistic knowledge.

* Related Article
Se Jin Oh, Jee Eun Sung, Sung Eun Lee, What Eye Movement Reveals Concerning Age-Related Dissociation in Syntactic Prediction: Evidence From a Verb-Final Language, Journal of Speech, Language, and Hearing Research, Volume 65 Issue 6, June 2022