| Summary: | 碩士 === 國立新竹教育大學 === 臺灣語言與語文教育研究所 === 96 === The aim of this study is to examine whether the activation of lexical meaning is similar for older and younger bilingual adults. Age-relation changes in lexical processing is examined and compared using event-relation potentials (ERPs) recorded as young and elderly participants listened to natural speech for comprehension. The Spreading Activation Model is adopted as our theoretical model for semantic processing.
In this study, ERPs are recorded as the older and younger subjects listen to the word pairs. Half of the stimuli (160 items) are semantically associated pairs, whereas the other half (160 items) are semantically irrelevant pairs. In selecting the word pairs, 80 categories were chosen first. Then a typical word (higher-associated) for the each category was decided, and then the typical word was matched with an atypical (lower-associated) and a semantically irrelevant word. The materials included 160 semantically related word-pairs (80 higher-associated and 80 lower-associated) and 160 semantically irrelevant word-pairs. 17 subjects (10 younger and 7 older) were asked to do a five-point scale rating for each word pair, as 5 for very high semantic association and 1 very low semantic association. The averages for each category are listed as following
The effects of semantically associated and semantically irrelevant word pairs are compared. Fourteen older Mandarin and Taiwanese bilingual adults (mean age: 61 years) and thirteen education-matched younger Mandarin and Taiwanese bilingual adults (mean age: 28 years) are tested. Both of them are tested with their first language, Taiwanese. The results show the decrease in N400 (time window between 300-600ms after the target appears) amplitude in non-associated and the increase in N400 peak are found in older subjects in high-associated. It suggests that "Aging" brings changes in the older.
Besides, the older group also shows a different pattern in semantic processing between higher associated pairs and lower associated pairs from the younger group. For the younger subjects, the activation of the lower associated pairs is in between of the higher associated pairs and irrelevant pairs. For the older subjects, the semantic links of high-associated pairs are much stronger than the semantic links between the lower associated pairs, whose semantic links become almost as weak as that of the irrelevant pairs. It is speculated that higher associated pairs remain strong links through frequent use, but the links between the lower associated pairs are trimmed as aging.
|
|---|
