Semantic Proximity Effects And Cognitive Aging In Lexical Processing

The influence of semantic cognition in language processing has always been one of the focal issues of psycholinguistics.The interactive activation model and competition theory shows that when people are processing words semantically,the semantic activation not only spreads to the target word,but also spreads to the semantic neighboring words.In the semantic network,the more semantic features shared by neighboring words and target words,the more similar they are in semantic representation,and the stronger the impact on target selection at the lexical level.Therefore,the study of semantic neighborhood density of target words is beneficial to people’s deep understanding of the characteristics of language processing.Compared with orthographic neighborhood density and phonological neighborhood density,the research on semantic neighborhood density is relatively less and mainly focuses on alphabetic study.Combined with the internal processing methods of Chinese characters,it is not clear how semantic neighborhood density influences and the direction of action in Chinese lexical processing.In addition,in some of the only researches on the semantic neighborhood density of alphabetic studies,the subjects are generally young people in the top of semantic cognition.However,the working memory,semantic retrieval and control of the elderly will change accordingly with the increase of age.At present,there are few studies on whether the semantic neighborhood effect is aging and the mechanism of aging.Therefore,research on the age difference and mechanism of semantic neighborhood effect not only provides evidence for the phenomenon of semantic aging,but also a further exploration in the field of neighborhood effect research.Combined with previous studies,the specificity of experimental tasks may cause different results of semantic neighborhood effect.Based on this,this study uses three semantic processing tasks that reflect different processing stages,and uses ERP technology with high behavioral and temporal resolution to compare the performance of young and old people in the three semantic tasks to investigate the influence of semantic neighborhood density on Chinese characters processing.In Experiment 1,we used the lexical decision paradigm to investigate the performance of semantic neighborhood effects and age differences between young and old.Behavioral results showed that neither young nor old subjects found semantic neighborhood effects.In the ERP results,both the young and the old induced P200,N400 and LPC components,and the statistical analysis of the amplitude did not find the difference in semantic neighborhood density between the two groups of subjects and the aging effect.However,compared with the young,the elderly have an earlier lantency of P200,N400,and LPC components.The above results indicate that there is no significant difference in the processing of high and low density target words between young and old in the lexical decision task,and the increase in age promotes the time course of lexical processing.In Experiment 2,we used the semantic category paradigm to investigate the performance of semantic neighborhood effects and age differences between young and old.Behavioral results showed that the semantic neighborhood effect of young people and old people is not obvious whether it is correctness or response time.As for the ERP results,young people have the facilitative effect of semantic neighborhood density on the N400 component,that is,compared with high density,the processing of low-density target vocabulary induces a larger N400 amplitude.However,there is no significant difference in lexical processing between high and low density in elderly subjects.The above results indicate that young people have the facilitative effect of semantic neighborhood in Chinese characters processing.The richer the semantic representation,the less mental resources consumed by lexical processing.With the decline of individual’s physiological structure and function,health aging affects the semantic density effect in lexical processing,which is more manifested as insufficient activation of high-density lexical.In Experiment 3,we used the picture naming task to investigate the performance of semantic neighborhood effects and age differences between young and old.The results showed that both the young and the old have the semantic neighborhood density effect in semantic processing.In terms of behavioral results,the accuracy of high-density words is higher,the reaction speed is faster,and the effect of facilitating semantic neighborhood appears.EEG results showed that in the N400 component that reflects semantic processing,the N400 amplitude induced by low-density word processing by young subjects was significantly greater than that of high-density words.But in the LPC component,we found the difference in semantic density effect aging,that is,the amplitude of the high-density words induced is greater than that of the low-density words.The above results show that the high semantic neighborhood density still plays a facilitative role in the time window of about 400 ms.However,in the later stage of lexical processing,the semantic processing of the elderly in high-density condition is relatively difficult,which is more related to the weak connection between semantic representation and phonological coding stage.The above results show that:(1)in Chinese lexical processing,when it comes to deep semantic access tasks,young people have the facilitative effect of semantic neighborhood density;(2)health aging affects the semantic density effect in lexical processing.Compared with young people,the facilitative effect of semantic neighborhood density in the lexical recognition task of the elderly disappears.In the spoken language generation task,the semantic neighborhood inhibition effect appears in the later stage of lexical processing;(3)there are differences in the intrinsic mechanism of semantic neighborhood density effect aging between word recognition and oral production.In the task of word recognition,the aging of the semantic neighborhood effect of the elderly may be related to the decline of general cognitive ability,which is more manifested as the insufficient activation of high-density lexical;while in the task of spoken production,the aging of the semantic neighborhood effect of the elderly may be more and The decline of language specificity is related to the lack of transmission between high-density word semantics and phonological coding.