Good Sleep is Good for Your Memory:
During the day our brains are constantly bombarded with new data. We meet new people. Memorize facts and figures. Listen to important details relating to work, friends and family members. And so much more!
Somehow, all of this information becomes stored in our memories. This enables us to ask a co-worker how her husband, John, is doing after his knee surgery, recall vital statistics when the boss asks for them, and recognize a new neighbor on sight.
While it’s a mystery how all of this works, we do know that sleep plays a significant role when it comes to consolidating the day’s events and placing them in permanent memory, as sleep is associated with a sharp mind and active body.
Neuroscientists at UC Berkeley believe that when we get deep, restorative sleep at night, it helps transfer the memories in your hippocampus — which provides short-term storage for memories — to the prefrontal cortex’s longer term “hard drive.”
Now, researchers from the University of York shed further light on how sleep helps make the most of our memories.
Sleep Has a Protective Effect on Memories
In a new analysis, researchers had two groups of people study the location of words on a computer screen. After this short memorization session, the participants were tested on their ability to recall where the words were placed.
For testing purposes, the words first appeared in the middle of a computer screen. Then the subjects had to indicate where they thought the words belonged based on their earlier memorization session.
At this stage of testing, there were no significant differences in memory performance between the two groups.
Afterward, one group slept for 90 minutes and the second group remained awake. Then each group was retested. However, the majority of words weren’t placed in the positions where they were originally studied. Instead, they were updated into positions closer to where they were retrieved in the first phase of testing.
In both groups, the location recalled at the second test was closer to that recalled at the first test than to the originally-learned location, indicating that memory updating had taken place and new memory traces had been formed.
However, those who slept between the sessions had better memory for both the updated location and the original location of the words. This suggests that a restful sleep has a protective effect on memories — actively updating and strengthening both new and old versions of our memories.
Using Your Memories in the Most Efficient Way Possible
Lead researcher Dr Scott Cairney said: “Previous studies have shown sleep’s importance for memory. Our research takes this a step further by demonstrating that sleep strengthens both old and new versions of an experience, helping us to use our memories adaptively.
“In this way, sleep is allowing us to use our memory in the most efficient way possible, enabling us to update our knowledge of the world and to adapt our memories for future experiences.”
However, there is one downfall that may occur. The research team points out that this process may also allow us to incorporate incorrect information into our memory stores. This is a phenomenon known as retrieval-induced distortion (RID).
This means that, over time, our memories may draw on both accurate and inaccurate versions of an experience at the same time. This can cause distortions in how we remember previous events and could explain why some memories tend to change and become fuzzy over time.