Looking back on even our favourite days can be a little hazy. While we’ll remember moments, feelings, and experiences that occurred, we’re unlikely to remember it minute-by-minute.
But, how does the brain choose what to hold onto from these days? Why do you remember the coffee that you had in that one city but not the conversation that accompanied it?
There is actually psychology behind this, and it essentially comes down to ‘ripples.’
How your brain selects memories
In an NYU study conducted on mice, which are often used in tests studying the human brain, researchers found that the brains of humans and other mammals have a system for choosing which life experiences are important enough to be stored into long-term memory — and which will fade away over time.
The experiments revealed that during waking hours, cells in the brain’s hippocampus spark in a specific pattern called “sharp-wave ripples,” which tag important experiences for movement into long-term memory storage during sleep.
As part of the research, the scientists put mice through a maze that ended with a sugary reward for those that reached it. As the mice were navigating the maze, researchers monitored the activity of nerve cells through electrodes implanted in the mice’s brains that fed data into computer programmes.
It’s during sleep when experiences from waking hours deemed to be important are converted into enduring memories.
Events that were followed by very few or no sharp-wave ripples failed to form lasting memories, the researchers noted.
This tagging process during waking hours is totally unconscious, Buzsáki said. “The brain decides on its own, rather than us deciding voluntarily,” he added.
As the mice tucked into their treats, their brains sparked ripples that were repeated up to 20 times. The daytime pattern of these ripples was replayed during the night, a process that researchers believe moved the experience into long-term memory.
What the researchers determined was that during sleep, our experiences from waking hours that are deemed to be important are converted into lasting memories.
Study author Dr. György Buzsáki said to NBC: “This tagging process during waking hours is totally unconscious. The brain decides on its own, rather than us deciding voluntarily.”
How we can select which memories to save
However, if you’re worried about forgetting memories that weren’t ‘tagged’ by your brain, Buzsáki said that taking pause is essential. Offering examples of film and TV, he said: “If you watch a movie and would like to remember it, it’s better to go for a walk afterwards. No double features.”
He also added, quite rightly, that if you binge a TV series, you’re only likely to remember the last episode that you watched.
Stopping to take it all in really is essential.