CAREER: The Neural and Cognitive Basis of Persisting Mental Content

Our memories help us to perform tasks in the world every day. For example, when we are out shopping, we use our memory to recall how many bananas we need to purchase, and after we leave the store, we use our memory to find our car in the parking lot. However, we do not only retrieve our memories intentionally. Instead, our memories powerfully affect our lives even when they are not related to our current task. For example, while we are standing in the fruit and vegetable aisles, we may find ourselves distracted from our shopping task, because our minds are full of memories of a personal conversation earlier in the day. More generally, we have all experienced ideas being “stuck in our heads” or finding that recent events are “on our minds”. In such cases, thoughts re-enter our minds without us actively seeking to retrieve them. The goal of this project is to understand what causes these persistent thoughts, how they emerge in the human brain, and their practical costs and benefits. They may impede our progress (for example, by reinforcing a negative mood) but could also aid us (for example, by generating the solution to a nagging problem). Researchers aim to investigate persisting mental content across two multipart studies. First, they investigate the brain mechanisms of persisting mental content. They hypothesize that persisting thoughts arise from the same brain processes that enable people to reinforce memories and generalize from past experiences. An experimental paradigm in which participants read or listen to immersive narrative is employed, which can be used to induce and measure persisting thoughts. Then functional neuroimaging and intracranial recordings measure each person’s brain activity before, during, and after narratives. In the same setting, the word-associations that participants generate are extracted along with any reports of persisting thoughts. In this way, they hope to map the brain networks and circuit processes that activate when thoughts involuntarily enter people’s minds. Second, the researchers focus on the question of why mental content persists, given that it can cause distraction or interference with a current task. They hypothesize that mental persistence can bridge interruptions in thinking, enabling complex problem solving and potentially deepening the understanding of a recent situation. To test this hypothesis, they use computational and behavioral methods to measure how persisting mental content affects our comprehension of sequences of situations and episodes. This work has powerful implications for understanding how the continuity of thought is impacted by, and protects against, the interruptions that we encounter in life. Overall, this program of research aims to uncover the mechanisms that generate persisting thoughts, as well as how to minimize the costs of persisting thoughts while maximizing their benefits. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.