The moment a person steps off the street and into a restaurant-;to take just one example-;the brain mentally starts a new "chapter" of the day, a change that causes a big shift in brain activity. Shifts like this happen all day long, as people encounter new environments, like going out for lunch, attending their kid's soccer game, or settling in for a night of watching TV. But what determines how the brain divides the day into individual events that we can understand and remember separately? That's what a new paper in the journal Current Biology aimed to find out.
The research team, led by Christopher Baldassano, an associate professor of Psychology, and Alexandra De Soares, then a member of his lab, turned up interesting results. The researchers wanted to better understand what prompts the brain to form a boundary around the events we encounter, effectively registering it as a new "chapter" in the day. One possibility is that new chapters are entirely caused by big changes in a person's surroundings, like how walking into a restaurant takes them from outdoors to indoors.
Another possibility, however, is that the new chapters are prompted by internal scripts that our brain writes based on past experience, and that even big environmental changes might be ignored by our brain if they are not related to our current priorities and goals. To test their hypothesis, researchers developed a set of 16 audio narratives, each about three to four minutes long. Each narrative took place i.