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They conducted the study to better understand just how human memory works. Credit: Neuroscience News

Why We Forget: New Insights into Everyday Memory

Summary: A new study investigates why everyday actions like locking a door are often forgotten. Researchers explored how people tend to remember significant events rather than routine details.

Their study revealed that while emotionally charged or unique events are initially memorable, even these can fade within 24 hours, particularly positive experiences. This research provides insight into the selective nature of memory and suggests that our brains prioritize and even forget information to manage cognitive load.

Key Facts:

  1. The study demonstrated that routine actions are easily forgotten due to their repetitive nature and lack of distinctiveness.
  2. Significant memories, especially positive ones, can also become less vivid or be forgotten after just 24 hours.
  3. The research suggests that memory is selective, with the brain focusing on conserving cognitive resources by prioritizing certain types of information over others.

Source: Rice University

We’ve all been in a similar situation—you lock your front door for the umpteenth time in a given week only to panic minutes later when you’re driving to work as you struggle to remember if you actually locked the door.

If this sounds familiar, you’re not alone, and you’re also not losing your mind. A new study published in Neurobiology of Learning and Memory by Rice University psychologists found that certain experiences are better remembered by most people, while other experiences, like locking the door behind us, are more easily forgotten.

However, the story isn’t quite that simple, according to researchers Fernanda Morales-Calva , a Rice graduate student, and Stephanie Leal , assistant professor of psychological sciences.

They conducted the study to better understand just how human memory works. They said humans tend to focus on remembering certain aspects within an experience more than others such as the big picture of what happened rather than the details.

“Struggling to remember is one of those things we all experience,” Morales-Calva said.

“But when it comes to understanding memory, there’s a lot to be discovered about how it actually works. And there’s a new area of memory research that’s trying to tap into why we remember certain things better than others.”

For example, Morales-Calva said people looking back on the last year may recall doing a lot of different things, but only a few of them might really stand out in great detail.

“Previous research has found that these memorable experiences for one person are very likely memorable for another person, like birthday parties, deaths of a loved one and more,” Leal said.

“These are often positive or negative experiences. This knowledge has helped us design research studies looking at memory performance.”

The researchers evaluated memory by showing pictures to their study participants. During a memory test, some of these images were repeated, some were brand new, while others were very similar and difficult to distinguish from one another.

These similar images were meant to interfere with memory, kind of like the similar daily experiences such as trying to remember if the door is locked. Memorable images were identified as the ones participants were most likely to recall.

Morales-Calva and Leal found that while participants correctly remembered the most memorable images, this effect was lost after 24 hours. This was especially true when remembering positive experiences, suggesting these experiences are memorable at first but more prone to be forgotten.

“While we feel like we know what types of experiences are memorable, we really don’t know what features of a memory are remembered best in the long term,” Morales-Calva said.

“We often think emotional memories are better remembered, but in fact gist versus detail trade-offs exist where the central features of the memory are enhanced while details may be forgotten.”

So if you’re one of the many people in the world who can’t remember if five minutes ago you put down your garage door or swallowed your medicine, the researchers said you’re not alone.

“Our brains can’t possibly remember everything we experience, and so we have to do a bit of selective forgetting for information that isn’t as important,” Leal said. “This study helps us get closer to understanding why we remember what we remember.”

Morales-Calva and Leal said they hope their findings will offer new insights into how memory works, and why some things are memorable and others are not.

They hope future studies will consider the complexity of memory in everyday life, including consideration of the emotional content, time that has passed since the experience and perceptual features of memory that may have significant impacts on what we remember.

About this memory research news

Author: Amy McCaig
Source: Rice University
Contact: Amy McCaig – Rice University
Image: The image is credited to Neuroscience News

Original Research: Open access.
Emotional modulation of memorability in mnemonic discrimination” by Fernanda Morales-Calva et al. Neurobiology of Learning and Memory


Emotional modulation of memorability in mnemonic discrimination

Although elements such as emotion may serve to enhance or impair memory for images, some images are consistently remembered or forgotten by most people, an intrinsic characteristic of images known as memorability.

Memorability explains some of the variability in memory performance, however, the underlying mechanisms of memorability remain unclear. It is known that emotional valence can increase the memorability of an experience, but how these two elements interact is still unknown.

Hippocampal pattern separation, a computation that orthogonalizes overlapping experiences as distinct from one another, may be a candidate mechanism underlying memorability. However, these two literatures have remained largely separate.

To explore the interaction between image memorability and emotion on pattern separation, we examined performance on an emotional mnemonic discrimination task, a putative behavioral correlate of hippocampal pattern separation, by splitting stimuli into memorable and forgettable categories as determined by a convolutional neural network as well as by emotion, lure similarity, and time of testing (immediately and 24-hour delay).

We measured target recognition, which is typically used to determine memorability scores, as well as lure discrimination, which taxes hippocampal pattern separation and has not yet been examined within a memorability framework.

Here, we show that more memorable images were better remembered across both target recognition and lure discrimination measures. However, for target recognition, this was only true upon immediate testing, not after a 24-hour delay.

For lure discrimination, we found that memorability interacts with lure similarity, but depends on the time of testing, where memorability primarily impacts high similarity lure discrimination when tested immediately but impacts low similarity lure discrimination after a 24-hour delay.

Furthermore, only lure discrimination showed an interaction between emotion and memorability, in which forgettable neutral images showed better lure discrimination compared to more memorable images.

These results suggest that careful consideration is required of what makes an image memorable and may depend on what aspects of the image are more memorable (e.g., gist vs. detail, emotional vs. neutral).

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