Using a TV episode and a geometrical model, researchers at Dartmouth have come up with a new way to understand how the brain evaluates which experiences to store as memories and which to discard.
The researchers based their study around participants’ recall of a BBC episode of Sherlock against a geometric model of the events that happened in it. Their results allowed new insights into how memories are stored and then related to others.
Senior author Jeremy R Manning, an assistant professor of psychological and brain sciences, and director of the Contextual Dynamics Lab at Dartmouth, explained: “When we represent experiences and memories as shapes, we can use the tools provided by the field of geometry to explore how we remember our experiences, and to test theories of how we think, learn, remember, and communicate.
“When you experience something, its shape is like a fingerprint that reflects its unique meaning, and how you remember or conceptualise that experience can be turned into another shape. We can think of our memories like distorted versions of our original experiences. Through our research, we wanted to find out when and where those distortions happen (i.e. what do people get right and what do people get wrong), and examine how accurate our memories of experiences are.”
Using a public dataset of brain recordings from 17 participants who had viewed the same Sherlock episode and described what had happened. This dataset also contained detailed notes on what took place in that episode. They took these notes to create a list of 32 topics, which were then represented as a 32-dimensional model. Visualised in 2 dimensions, a dot-to-dot shape emerges, to which the shapes made by the participants’ recall of events can be compared.
Using the episode’s shape as a structure, they were able to see at what points the participants’ memories matched the episode, and what points they forgot or had distorted recollections. The shape also featured extraneous elements of fine detail, like architectural embellishments such as carvings, which reflected low-conceptual details. Some participants accurately recounted these low-conceptual details while others could only recall high-level plot points.
“One of our most intriguing findings was that, as people were watching the episode, we could use their brain activity patterns to predict the distorted shapes that their memories would take on when they recounted it later,” explained Manning. “This suggests that some of the details about our ongoing experiences get distorted in our brains from the moment they are stored as new memories. Even when two people experience the same physical event, their subjective experiences of that event start to diverge from the moment their brains start to make sense of what happened and distill that event into memories.”
These findings could be used as the basis for research into improving educational delivery, as well as patients’ understanding of matters explained to them by their doctors.
Source: Medical Xpress
Journal information: Geometric models reveal behavioural and neural signatures of transforming experiences into memories, Nature Human Behavior (2021). DOI: 10.1038/s41562-021-01051-6
