不同类型的一体化编码对青年人和老年人在联结记忆任务中项目再认的影响

The influence of different types of unitization strategies on the item recognition comprising the unitized association tasks in both younger and older adults

使用脑电探究不同的一体化对联结记忆任务中项目再认的影响及其相关的神经机制。两个实验分别使用复合词和定义操作自下而上和自上而下一体化。青年人的行为结果发现两种一体化的联结再认相当,项目再认也无显著差异。脑电结果发现复合词减少了顶区新/旧效应,定义缺失额区新/旧效应,说明青年人依据较少的神经活动达到相当的行为表现,支持“只有收益”观点。老年人的结果发现两种一体化都能提高联结再认,但对项目再认的影响不同。复合词在促进联结再认时也促进了项目再认,脑电结果发现仅在复合词下存在额区新/旧效应,显示复合词促进项目再认可能是源于熟悉性的增加,支持“只有收益”的观点。定义在促进联结再认时损害了项目再认,脑电结果发现定义缺失额区新/旧效应,显示定义对项目再认的损害可能源于熟悉性的缺失,支持“收支平衡”的观点。这些结果表明一体化促进还是损害老年人项目再认取决于自下而上和自上而下的一体化对认知资源的需求情况。

This study used event related potential(ERP)technology to investigate the effects of different types of unitization on item recognition in both younger and older adults through two experiments.A total of two theoretical accounts concern the role of unitization in both item and associative recognition:“benefits and costs”and“benefits-only”accounts.This study hypothesized that because young adults have more cognitive resources,either type of unitization with different demands on cognitive resources does not impair their item memory.However, older adults have fewer cognitive resources, and whether different types of unitization impair theiritem memory depends on how these demand cognitive resources. Experiment 1 manipulated the level ofbottom-up unitization by using compound words and unrelated words. Experiment 2 manipulated the level oftop-down unitization using definition and sentence.In experiment 1, a total of 19 community-dwelling older and 23 younger adults were asked to learncompound and unrelated word pairs, and during tests, they were asked to perform item recognition andassociative recognition tasks. In experiment 2, a total of 19 community-dwelling older adults and 20 youngeradults were asked to learn word pairs under definition and sentence conditions, and during the test they wererequired to perform item recognition and associative recognition tasks. In our sample of two experiments, allOlder adults completed the mini mental state examination and scored at least 26 pointsFor younger adults, two types of unitization condition had no effect on their associative and itemrecognition. The ERP results of Experiment 1 revealed a comparable frontal old/new effect in both compoundwords and unrelated words condition, and the compound words condition reduced the parietal old/new effect.The ERP results of Experiment 2 indicated that the frontal old/new effect was absent in the definition condition,and both unitization conditions revealed a comparable the parietal old/new effect. For older adults, two types ofunitization enhanced their associative recognition, however, have different influence on the item recognition.The behavioral results of Experiment 1 showed that older adults’ item recognition performance under thecompound words condition was superior to that under the unrelated words condition. The ERP results indicatedthat the frontal old/new effect was only present in the compound words condition, and both encoding conditionsrevealed a comparable the parietal old/new effect. The behavioral results of Experiment 2 showed that olderadults’ item recognition performance under the definition condition was inferior to that under the sentencecondition. The ERP results revealed that the frontal old/new effect was absent in definition condition and onlypresent in the sentence condition, and both encoding conditions were found to have comparable parietal old/neweffect.The influence of unitization on the item recognition depends on the encoding types. For younger adults, theitem recognition in both unitized encoding conditions were comparable to that in the non-unitized encoding.Equivalent levels of memory retrieval were achieved through “less” overall neural processing on familiarity orrecollection, which supports the “benefits-only” account. For older adults, the bottom-up unitized encodingcondition promotes item recognition relying on the frontal old/new effects, which supports the “benefits-only”account. The top-down unitized encoding condition impaired older adults’ item recognition relying on the absentof the frontal old/new effects, which supports the “benefits and costs” account.