Author ORCID Identifier
Date of Award
Department or Program
Psychological & Brain Sciences
Humans possess a unique and wide-ranging ability to self-reflect that takes center stage in our everyday cognition. While many people believe their own self to be immutable, different contexts may warp how we perceive the self. The goal of this dissertation is to investigate two lenses through which we may view the self: (1) across time in the past and future, and (2) through the eyes of others via evaluative feedback. In Studies 1-3, I demonstrate that people’s ratings of their own personality become increasingly less differentiated as they consider more distant past and future selves. This effect was preferential to the self and could not be explained by the alternative possibility that individuals simply perceive arbitrary self-change with time irrespective of temporal distance. In Study 4, I found neural evidence in areas of the default network—including medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC)—that the brain compresses self-representations with time, as well. In Study 5, I delivered feedback to participants that was either consistent or inconsistent with their own self-views. While self information was privileged in memory compared to learning about someone else, I found that this enhancement was driven by better memory for self-inconsistent feedback (relative to inconsistent feedback about another person). Further, brain states associated with encoding self-inconsistent feedback within the right ventral anterior insula (vAI) and dorsal medial prefrontal cortex (DMPFC) are carried over into post-encoding rest. Finally, individual differences in the number of self-inconsistent reinstatements within right vAI corresponded to better memory for self-inconsistent feedback. Within DMPFC, the correspondence between self-inconsistent reinstatements and self-inconsistent memory assumed an inverted U-shaped relationship, such that people who reinstated the most and the least performed worse in remembering self-inconsistent information compared to people in the center of the distribution. Taken together, these studies demonstrate that neural architecture supports the perception of a malleable self that changes based on the perspective we perceive it. Interventions that help bring the self into clearer view may both aid in decision-making for future planning and help buffer the emotional blows that come with engaging in a social world.
Brietzke, S., & Meyer, M. L. (2021). Temporal self-compression: Behavioral and neural evidence that past and future selves are compressed as they move away from the present. Proceedings of the National Academy of Sciences of the United States of America, 118(49). https://doi.org/10.1073/pnas.2101403118
Brietzke, Sasha Carmela, "Mapping the Malleable Self: How Self-Views are Represented and Learned Within the Social Brain" (2023). Dartmouth College Ph.D Dissertations. 139.