Doctor of Philosophy
New experiences take time to be incorporated into memory structures, and this process of memory integration is called consolidation (Müller & Pilzecker, 1900; Ribot, 1882). As new experiences integrate into existing structures, the contextual details surrounding them are assumed to be stripped away, making it difficult to distinguish between similar experiences. Underlying this process is a time-dependent shift in the brain areas supporting representation and retrieval of memories. While new experiences require interaction between neocortex and the hippocampus for retrieval, older memories are assumed to be supported entirely by neocortex (Squire & Alvarez, 1995).Several factors surrounding new experiences may alter the time course of consolidation and retrieval of detail. I conducted four experiments assessing how these factors influence consolidation and detail access. Experiments 1a and 1b asked whether integrating new information into schemas accelerates the time course of consolidation, such that schema-congruent information is remembered in less detail than schema-incongruent information. Neither experiment supported this hypothesis; rather, schema-congruent information was remembered in more detail than schema-incongruent information. Experiment 2 assessed how stress following an experience alters consolidation. I proposed that consolidation under moderate stress may preserve details while extreme stress may lead to detail loss relative to stress-free conditions. To test this, participants were exposed to a physiological stressor after encoding. While my hypothesis was not supported, I found a negative relationship between individual stress responses and detail memory in participants who responded to the stressor with an increase in cortisol. Experiment 3 explored whether detail memory could be preserved if details were predictively relevant for future encounters. I instantiated predictive relevance by exposing participants to multiple exemplars from the same category, with some exemplars paired with an aversive tone and others with a neutral tone. This contrast signaled that details are relevant to distinguish between aversive and neutral stimuli. Contrary to my predictions, exemplars paired with an aversive tone were not remembered with more detail than control exemplars. These findings are discussed with respect to the time course of consolidation, potential encoding vs. consolidation differences triggered by the manipulations, and previous findings in animal and human memory.
Sabia, Matthew Thomas, "The Time Course Of Memory Consolidation: Factors Influencing What Can Be Retrieved From An Experience Over Time" (2019). Theses and Dissertations. 5616.