Ladd Sandra L, Gabrieli John D E
Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, United States.
Front Aging Neurosci. 2024 Oct 9;16:1454867. doi: 10.3389/fnagi.2024.1454867. eCollection 2024.
Disproportionally better memory for positive versus negative information (mnemonic positivity effect, MPE) in older versus younger adults has been reported on tests of explicit memory (direct, intentional) as measured by recall and recognition. The purpose of this investigation was to examine whether the MPE would be observed for implicit memory (indirect, unintentional) under conditions where, based on previous research using single words, it was expected that the MPE for explicit memory would be absent.
This study investigated the influence of age on explicit and implicit memory for positive, negative, and neutral single words as measured by yes/no recognition and word identification on 24 older adults (aged 66-85) and 24 younger adults (aged 18-37) recruited from community centers in South Boston, Massachusetts.
Older adults had lower recognition memory accuracy for positive, negative, and neutral words than younger adults, and, consistent with most prior studies, did not exhibit an explicit memory MPE for single words. For both groups, recognition accuracy was greatest for negative words, and was similar for positive and neutral words. In contrast, older adults exhibited implicit repetition priming, as measured by superior identification performance for repeated words, that was similar to younger adults for positive and neutral words. In younger adults, implicit memory was significantly greater for negative words than for positive and neutral words, whereas in older adults there were no significant differences in implicit memory for negative, positive, and neutral words. Therefore, selectively reduced priming for negative words in older adults was found in the context of enhanced priming for negative words in the younger adults.
These findings show that there was an implicit memory MPE in older adults for words even under conditions where there was no explicit memory MPE in the older adults. Dampening of negative valence implicit memory with aging expands the perimeter of the age-related positivity framework.
在通过回忆和识别测量的外显记忆（直接、有意）测试中，已有报道称老年人与年轻人相比，对积极信息与消极信息的记忆存在不成比例的差异（记忆积极效应，MPE）。本研究的目的是在基于先前对单个单词的研究预期外显记忆不存在MPE的条件下，检验内隐记忆（间接、无意）是否会出现MPE。
本研究调查了年龄对积极、消极和中性单个单词的外显和内隐记忆的影响，通过是/否识别和单词识别对从马萨诸塞州南波士顿社区中心招募的24名老年人（66 - 85岁）和24名年轻人（18 - 37岁）进行测量。
老年人对积极、消极和中性单词的识别记忆准确性低于年轻人，并且与大多数先前研究一致，老年人对单个单词未表现出外显记忆MPE。对于两组，消极单词的识别准确性最高，积极和中性单词的识别准确性相似。相比之下，老年人表现出内隐重复启动效应，通过对重复单词的卓越识别表现来衡量，对于积极和中性单词，其与年轻人相似。在年轻人中，消极单词的内隐记忆显著大于积极和中性单词，而在老年人中，消极、积极和中性单词的内隐记忆没有显著差异。因此，在年轻人对消极单词启动增强的背景下，发现老年人对消极单词的启动选择性降低。
这些发现表明，即使在老年人不存在外显记忆MPE的条件下，老年人对单词也存在内隐记忆MPE。随着年龄增长，消极效价内隐记忆的减弱扩展了与年龄相关的积极框架的范围。
