Browsing by Author "Umanath, Sharda"
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Item Open Access Age Differences in Suggestibility Following Semantic Illusions: The Role of Prior Knowledge(2014) Umanath, ShardaIn the face of declines in memory related to specific events, people maintain intact general knowledge into very old age. Older adults often use this knowledge to support their remembering. Semantic illusions involve situations in which presented information contradicts correct knowledge; the illusion occurs when people fail to notice a contradiction with what they know. Compared to younger adults, older adults' later memories are surprisingly less affected by semantic illusions. That is, they use fewer errors seen in the semantic illusions as answers when later asked related general knowledge questions. Why do older adults show this reduced suggestibility, and what role does their intact knowledge play? In 5 experiments, I explored these questions. Older adults' reduced suggestibility was not due to an age difference in error detection: older adults were no better than younger adults at detecting the errors that contradicted their stored knowledge. In addition, episodic memory failures were not a major factor either; the evidence for their direct involvement was mixed. Instead, prior knowledge seems to have been particularly protective for older adults. They demonstrated more knowledge to begin with but also gained access to even more of their stored knowledge across the duration of experiments, leading them to be less suggestible following semantic illusions. There was also an indication that when knowledge was stably accessible, older adults had a tendency to rely on it more than did younger adults. Broadly, these findings indicate that older adults' intact prior knowledge provides important benefits to their remembering and can even protect them against acquiring erroneous information about the world.
Item Open Access Event memory: A theory of memory for laboratory, autobiographical, and fictional events.(Psychol Rev, 2015-01) Rubin, David C; Umanath, ShardaAn event memory is a mental construction of a scene recalled as a single occurrence. It therefore requires the hippocampus and ventral visual stream needed for all scene construction. The construction need not come with a sense of reliving or be made by a participant in the event, and it can be a summary of occurrences from more than one encoding. The mental construction, or physical rendering, of any scene must be done from a specific location and time; this introduces a "self" located in space and time, which is a necessary, but need not be a sufficient, condition for a sense of reliving. We base our theory on scene construction rather than reliving because this allows the integration of many literatures and because there is more accumulated knowledge about scene construction's phenomenology, behavior, and neural basis. Event memory differs from episodic memory in that it does not conflate the independent dimensions of whether or not a memory is relived, is about the self, is recalled voluntarily, or is based on a single encoding with whether it is recalled as a single occurrence of a scene. Thus, we argue that event memory provides a clearer contrast to semantic memory, which also can be about the self, be recalled voluntarily, and be from a unique encoding; allows for a more comprehensive dimensional account of the structure of explicit memory; and better accounts for laboratory and real-world behavioral and neural results, including those from neuropsychology and neuroimaging, than does episodic memory.Item Open Access Scenes enable a sense of reliving: Implications for autobiographical memory.(Cognition, 2019-02) Rubin, David C; Deffler, Samantha A; Umanath, ShardaAutobiographical memory has been defined by the phenomenological properties of reliving, vividness, and belief that an event occurred. Neuropsychological damage that results in the inability to recall the layout of a scene also results in amnesia suggesting a possible milder effect in people without such neurological damage. Based on this and other observations, we hypothesized that the degree to which the layout of a scene is recalled will correlate positively with ratings of reliving, vividness, and belief, and will explain more variance in multiple regressions than recalling the scene's contents. We also hypothesized that a lack of layout underlies nonspecific autobiographical memories which are common in aging, future events, and clinical disorders, whereas currently such memories are most commonly measured by reports of extended duration. We tested these theory-driven novel hypotheses in three studies to replicate our results. In each study, approximately 200 participants rated the layout, content, and other properties of personal events. Correlational analyses in each study and a structural equation model for the combined studies provide strong support for the role of mental scene construction in an integrative neurocognitive approach to clarify cognitive theory and clinical phenomena.