From the moment a person transitions from the street to step inside a restaurant, their brain marks the beginning of a new “chapter” in their day. This mental segmentation triggers significant changes in brain activity. This phenomenon occurs frequently as we navigate different settings — a casual lunch out, attending a child’s soccer match, or settling down for an evening in front of the television.
A recent study, a pioneering work in the field, published in the journal Current Biology investigates how our brains divide the day into discrete, comprehensible, and memorable events. The study, spearheaded by Christopher Baldassano, an associate professor of Psychology, and Alexandra De Soares, a former lab member, sheds light on this intriguing cognitive process.
The researchers sought to deepen our understanding of what instigates the brain to delineate these boundaries, thereby registering our daily experiences as distinct “chapters”. One theory posits that these divisions are primarily influenced by significant environmental changes, such as transitioning from an outdoor setting into a restaurant. Alternatively, the study explores whether these “chapters” could be shaped by internal narratives scripted by the brain based on past experiences, suggesting that even major environmental shifts might be overlooked if they do not align with our immediate priorities and goals.
To explore these theories, the research team designed an experiment involving 16 audio narratives, each lasting between three and four minutes. These narratives were set in various locations—a restaurant, an airport, a grocery store, and a lecture hall—and revolved around different social interactions, including a breakup, a marriage proposal, a business transaction, and a casual encounter.
The study revealed that the brain’s method of segmenting experiences highly depends on individual priorities and focus points. For instance, when subjects listened to a narrative about a marriage proposal in a restaurant, their prefrontal cortex typically organised the story around the proposal event, climaxing at the anticipated “yes.” However, when instructed to concentrate on different aspects of the narrative, such as the couple’s dinner orders, these mundane details transform into pivotal “chapters” of the narrative.
Christopher Baldassano highlighted an intention to challenge the notion that the brain passively responds to environmental changes without active involvement in crafting new cognitive chapters. The findings suggest that the brain is indeed actively engaged in structuring our life experiences into meaningful segments, a process that keeps us actively involved in our own memories.
This segmentation process was further analysed using MRI scans to track new brain activity and, alternatively, by instructing another group of participants to indicate when they perceived new story segments by pressing a button. It was observed that the brain segments narratives based on the instructed perspective, applicable across different scenarios, whether it involved a breakup at an airport or a business deal in a grocery store. The details that participants focused on significantly shaped their perception of new narrative chapters.
The researchers aim to continue exploring how expectations affect long-term memory retention. Preliminary tasks involved participants recounting what they remembered from each story, with ongoing analysis to understand how adopted perspectives during the narratives influence memory recall. This study is part of a broader effort to develop a comprehensive theory on how real-life experiences are segmented into event memories, emphasising the role of prior knowledge and expectations in this cognitive process. We invite you to stay connected with our ongoing research.
Baldassano views this work as a passion project. He points out the complexities involved in tracking brain activity patterns over time and utilising mathematical models alongside meaningful narratives to unveil new insights into cognitive processes. His enthusiasm for this unconventional approach underscores the innovative nature of the research conducted in his lab.
More information: Alexandra De Soares et al, Top-down attention shifts behavioral and neural event boundaries in narratives with overlapping event scripts, Current Biology. DOI: 10.1016/j.cub.2024.09.013
Journal information: Current Biology Provided by Columbia University
