Phonological Proximity Effect And Cognitive Aging In Lexical Processing

Successful recognition of a word requires the person to match phonological input to the correct lexical entry in the mental lexicon.This entail identifying the perceived word from among tens of thousands of word forms,some of them are acoustically similar to the target words.The phonological neighbors of alphabetic characters refer to the words that can be formed by changing one phoneme of the target words.In the phonological processing,the phonological neighbors are activated as well as the target words,and the extraction of the phonological neighborhood could promoted or inhibited the retrieved of target words through feedback activation and competition.Therefore,the number of phonological neighbors(phonological neighborhood density)of the target words will affect the performance of word recognition,and the phonological neighborhood effect will appear.The phonological neighborhood effects affects word recognition performance through two processes: activation and competition.However,the older adults generally experience a decline in activation and inhibition capabilities,which may change the impact of the phonological neighborhood effects of them.In addition,research based on alphabetic characters found that both audiovisual and audio channels have phonological neighborhood effects.And affected by input characteristics and orthographic factors,the phonological neighborhood effects under different channels have different performances.A large number of studies about Chinese have shown that phonetic information is also activated in written and reading processing.Therefore,the phonological neighborhood effects may still play an important role in Chinese visual word recognition,and it is different from the performance in auditory vocabulary recognition because the input method and orthography.However,the current domestic related researches have only conducted preliminary explorations on the phonological neighborhood effects of young people.No research has focused on the impact of aging on the phonological neighborhood effects,and most of the studies are limited to observing the voice proximity effect under a single channel.Therefore,this study designed two experiments to explore the phonological neighborhood effects and cognitive aging in Chinese word recognition,revealed the mechanism of aging on the phonological neighborhood effects,and compared the channel differences on this basis.In Experiment 1,ERP technology and the auditory lexical decision task were used to study the phonological neighborhood effect of young adults and older adults.The experiment uses the Chinese syllables as target words which have high or low density,and controlling the influence of homophonic character count and frequency.Experimental results showed that:(1)the behavioral results showed that phonological neighborhood density facilitates auditory word recognition: words from high density phonological neighborhood are responded to more quickly and accurately in a lexical decision task;(2)EEG results: for young adults,density modulated the amplitude of both the P200 and the N400.For older adults,density modulated only the amplitude of the P200.The results indicated that transmission deficits in auditory vocabulary recognition may be an important reason for the changes in the phonological neighborhood effect of the older adults.According to the young adults,word recognition can be facilitative by bottom-up activation form phonology to semantics.However,the activation transmission from shared phonemes to lexical nodes showed an age-related decline,the promotion effect of high-density words was reduced.In experiment 2,ERP technology and the visual lexical decision task were used to study the phonological neighborhood effect of young adults and older adults.The experiment uses the Chinese characters as target words which corresponding to the high and low density syllables of Experiment 1.The influence of frequency of the target words and number of strokes are controlled.Experimental results showed that:(1)the behavioral results showed that phonological neighborhood density inhibits visual word recognition: words from low density phonological neighborhood are responded to more quickly and accurately in a lexical decision task;(2)EEG results: for young adults,density modulated the amplitude of both the P200 and the LPC/P300.In contrast,effects of density in older adults were disappeared in both P200 and LPC/P300.For older adults,density modulated only the amplitude of the P200.The results indicate that insufficient activation in visual vocabulary recognition may be an important reason for the changes in the phonological neighborhood effect of the older adults.Compared with young adults,the cognitive resources of the older adults are too few to provide support in the activation of voice information.The phonological neighborhood of the target words may not be fully activated,thus the density difference will not affect the visual word recognition of the older adults.Comprehensive conclusion of experiment 1and experiment 2: Chinese visual and auditory word recognition both have phonological neighborhood effect.However,under auditory conditions,it is manifested as a facilitates effect,and under visual conditions it is manifested as an inhibits effect.Aging will change the phonological neighborhood effect of the older adults.In the auditory task,the spreading activation to the semantics of lexical neighbors appears to be reduced in adult aging,supporting the transmission deficits hypothesis.In the visual task,the phonetic neighboring words cannot be fully activated to affect the vocabulary recognition performance of the elderly,which supports the insufficient activation hypothesis.