EFFECTS OF AGING ON MEMORY FOR SOURCE OF INFORMATION

与年轻人相比，老年人不仅在记忆内容方面有困难，而且在记忆信息来源（如说话者、时间或空间背景、情态）方面也有困难。随着人口老龄化，这种自传式或“情节”记忆的丧失将影响越来越多的人。能够记住信息而不记得信息来源的潜在实际后果是多方面的——从记住将药品存放起来而不记得放在哪里的挫败感，到在目击情况下对错误记忆的潜在脆弱性增加或妄想的发展。本研究的重点是情景记忆的检索和评价阶段（源监测）。这些过程在自我启动或反思活动的程度上有所不同。启发式过程相对简单，涉及基于现成信息的简单匹配。系统过程更复杂（受控），包括自我启动的检索和简单过程的迭代。现有证据表明，随着任务的反思要求越来越大，老年人更有可能表现出缺陷。此外，来自脑损伤人群和神经影像学研究的证据表明，前额叶皮层（PFC）对情景记忆很重要。基于新的文献分析和我们的初步发现，我们假设右侧PFC区域服务于相对启发式的过程，而左侧PFC或左右PFC之间的双边合作服务于更系统化的过程。我们还提出，与年龄相关的源监测下降的生理基础主要是由于左侧PFC的功能障碍，或左右PFC的相互作用。我们使用自然主义（例如，目击者记忆，说话人识别）任务来评估多维记忆的监测，并使用更简单的任务来分离源监测的各个组成过程。记忆质量的主观评分与源记忆的更客观的行为测量相结合，以评估源监测的离散和连续定量模型的充分性。认知/行为方法与功能磁共振成像成像技术相结合，研究来源归因过程子组件的潜在年龄相关差异及其神经基础，包括使用多个决策维度的能力降低，在维度之间切换的难度增加，以及在一个或多个维度上维持适当标准的难度增加。

Compared to younger adults, older adults not only have difficulty remembering the content but, especially, they have problems in remembering the source (e.g., speaker, temporal or spatial context, modality) of information. Such a loss of autobiographical or "episodic" memory will affect an increasing number of people as the population ages. The potential practical consequences of being able to remember information, but not its source, are far-ranging-from the frustration of remembering puffing medicine away for safekeeping but not where, to potential increased vulnerability to false memories in eyewitness situations or to the development of delusions. The proposed research focuses on the retrieval and evaluation phase of episodic remembering (source monitoring). These processes vary in degree of self-initiated or reflective activity. Heuristic processes are relatively simple, involving easy matches based on readily available information. Systematic processes are more complex (controlled), involving self-initiated retrieval and iterations of simpler processes. Available evidence suggests that as the reflective demands of tasks become greater, older adults are more likely to show deficits. Furthermore, evidence from brain damaged populations and from neuroimaging studies, suggests that prefrontal cortex (PFC) is important for episodic remembering. Based on a new analysis of the literature and our preliminary findings, we hypothesize that regions in right PFC subserve relatively heuristic processes and that left PFC or bilateral cooperation between right and left PFC subserve more systematic processes. We also propose that the physiological basis for age- related declines in source monitoring is largely due to dysfunction of processes that recruit left PFC, or the interaction of right and left PFC. We use naturalistic (e.g., eyewitness memory, speaker identification) tasks for assessing the monitoring of multidimensional memories and simpler tasks to isolate various component processes of source monitoring. Subjective ratings of qualities of memories are combined with more objective behavioral measures of source memory to assess the adequacy of discrete and continuous quantitative models of source monitoring. A cognitive/behavioral approach is combined with fMRI imaging techniques to investigate potential age-related differences in, and the neural basis of, subcomponents of source attribution processes, including reduced ability to use multiple decision dimensions, greater difficulty switching between dimensions, and difficulty maintaining appropriate criteria on one or more dimensions.