Situation Model Updating in Young and Older Adults

描述（由申请人提供）：老年人报告的主观记忆抱怨涉及日常活动的记忆，例如忘记他们放置物品的位置，忘记到熟悉地点的方向，重复故事。然而，令人惊讶的是，在自然的日常事件背景下，与年龄相关的记忆变化却没有得到研究。最近，我们开始了解人们如何构建和更新他们所经历或读到的事件的表征。活动是动态的，因此“现在正在发生什么”的表示（即，情况模型）必须不断更新。记忆更新和容量的下降与衰老有关；因此，老年人更新情境模型的方式可能与年轻人不同。当几个维度（包括角色、目标、空间和时间）中的至少一个维度发生变化时，情况模型就会更新。一种可能性是，所有情况模型更新都是增量的，其中只更新与变化维度相关的信息。或者，可以全局更新情况模型。在这个视图中，动态活动被分割成离散的事件，这些事件在情况模型中表示。活动在事件边界处被分割，当一个新事件开始时，整个模型被更新——而不仅仅是被更改的信息。鉴于全球更新的证据很少，本项目旨在检验(1)情境模型是否具有全球更新，(2)更新过程是否受年龄的影响。为了评估这些目标，年轻人和老年人将阅读叙事性文本。内存将沿着一个维度（例如，空间）的变化触发的事件边界进行探测。如果我们发现了全局更新的证据，那么在事件边界之后，与前一个事件相关的所有信息都将变得不那么可用。然而，如果更新是增量的，那么我们应该发现只有与已更改维度相关的信息可用性较低。最后，当参与者阅读叙述时，功能性磁成像将被用来观察与年龄相关的相活动差异对记忆探针的反应。如果情境模型在事件边界被全面更新，那么所有的探针都应该选择性地激活内侧颞叶——与长期记忆提取相关的区域。如果情景模型是增量更新的，那么改变维度的探针应该激活内侧颞叶，而不变维度的探针应该激活与情景模型检索相关的前额叶皮层区域。该项目对理解理论以及认知衰老干预具有启示意义。

DESCRIPTION (provided by applicant): The subjective memory complaints reported by older adults involve memory for everyday activities, such as forgetting where they placed items, forgetting directions to familiar locations, and repeating stories. Yet, age-related changes in memory in the context of naturalistic everyday events have gone surprisingly unstudied. Recently, we have begun to understand how people build and update representations of events they experience or read about. Activity is dynamic, so the representation of "what is happening now" (i.e., situation model) must be updated constantly. Decreased memory updating and capacity are associated with aging; thus, older adults may update situation models differently than do young adults. Situation models are updated when a change has occurred along at least one of several dimensions, including characters, goals, space, and time. One possibility is that all situation model updating is incremental in which only information relevant to the changing dimension is updated. Alternatively, situation models may be globally updated. In this view, dynamic activity is segmented into discrete events that are represented in the situation model. Activity is segmented at an event boundary, and when a new event begins, the entire model is updated-not just the information that changed. Given that little evidence exists for global updating, this project aims to test whether (1) situation models are updated globally and (2) the updating process is affected by age. To assess these aims, young and older adults will read narrative texts. Memory will be probed following an event boundary triggered by a change along one dimension (e.g., space). If we find evidence of global updating, then all information related to the previous event will be less available after an event boundary. However, if updating is incremental, then we should find that only information associated with the changed dimension is less available. Finally, while participants read narratives, functional magnetic imaging will be used to look at age-related differences in phasic activity in response to memory probes. If situation models are updated globally at event boundaries, then all probes should selectively activate the medial temporal lobes-regions associated with retrieval from long-term memory. If situation models are updated incrementally, then the changed-dimension probes should activate the medial temporal lobes, whereas the unchanged-dimension probes should activate prefrontal cortex-region associated with retrieval from a situation model. This project has implications for theories of comprehension as well as cognitive aging interventions. PUBLIC HEALTH RELEVANCE: Declines in memory for everyday events are one of the common complaints of aging. Recent research with younger adults suggests that "chunking" ongoing activity into meaningful events is important for later memory. The proposed studies will investigate how the mind and brain do this chunking as people read text and how this process changes with age.