Author: Xie, Chenwei
Title: An experimental investigation into older adults of production/comprehension asymmetries and declarative/procedural memory contributions: a Chinese context
Advisors: Wang, Shiyuan William (CBS)
Degree: Ph.D.
Year: 2023
Subject: Older people -- Language
Language acquisition
Asymmetry (Linguistics)
Hong Kong Polytechnic University -- Dissertations
Department: Department of Chinese and Bilingual Studies
Pages: 215 pages : color illustrations
Language: English
Abstract: Children tend to experience an asymmetry in production and comprehension as their language develops. However, it remains unclear whether older adults exhibit such production/comprehension asymmetry (PCA) in a retrogenic manner. The overarching target of the current study is to examine whether PCA exists in the syntactic and semantic abilities of older adults. As language ability is correlated with various cognitive abilities, we further probe whether PCA is associated with the declarative and procedural memory, since semantic and syntactic abilities are considered to be subserved by declarative and procedural memory, based on the declarative/procedural model.
The declearn task was used and the serial reaction time task was administered in order to measure declarative memory and procedural memory, respectively. It was found that both declarative memory and procedural memory deteriorated in older adults. Our results also demonstrate that the erasure of items in declarative memory follows the retrogenesis theory. As adults age, they tend to remember more real objects and forget more made-up objects; this pattern is the reverse of that in childhood.
Using production tasks and comprehension tasks, we systematically investigated the syntactic and semantic processing patterns in the Chinese population, especially in older Chinese people. The results indicated that although older adults were able to express relevant information with intact syntactic and semantic complexity, they required a greater amount of planning time to initiate sentence production than younger adults. It was determined that older adults had a significantly lower level of semantic comprehension compared to younger adults because of their relatively low accuracy rate, as well as the absence of the N400 effect. On the other hand, it was shown that older adults were capable of reaching a similar accuracy rate as younger adults when judging syntactic correctness. Despite this, older adults failed to exhibit the anterior negative effect that could be observed in the neural potential of younger individuals. Thus, there are behavioral and neural differences in the receptive syntactic abilities of older adults.
According to our findings, the semantic performance of older adults fluctuated in terms of receptive modality and expressive modality, resulting in a semantic PCA similar to that of children. The findings are in accordance with the retrogenesis theory, which posits that the decline of language reverses the trajectory of its development. Additionally, we found that the asymmetry between semantic production and comprehension emerged after both behavioral and neural declines in semantic ability. It is also important to note that the asymmetry may be hidden at the behavioral level and only visible at the level of neural activity.
Furthermore, we found that declarative/procedural memory was associated with semantic/syntactic performance in adults of all ages. In addition, the original declarative/procedural model has been extended in the current study, as the two memory systems tend to be unequally linked to language abilities in the expressive modality and receptive modality. It is likely that the lifelong unequal associations contribute to PCA.
The findings of our study provide a comprehensive picture of age-related memory deficits and language attrition, as well as behavioral and neural mechanisms responsible for these declines. The results of our research on retrogenic production and comprehension asymmetries indicate that we have a responsibility to treat the elderly with the same care and attention offered to our children.
Rights: All rights reserved
Access: open access

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Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/12295