Psychologists Reveal Why You Can't Remember if You Locked Your Front Door

Scientists are a step closer to understanding why we remember some things and forget others.

Researchers at Rice University in Houston, Texas, conducted a study that found that we tend to remember certain aspects of an experience such as the big picture or the general context, rather than the smaller details.

Therefore, we're more likely to forget the smaller, mundane experiences, like whether we locked the front door.

To better understand how human memory works, graduate student Fernanda Morales-Calva and assistant professor Stephanie Leal showed pictures to 38 study participants.

During a memory test, some of the images were repeated while others were brand new.

Some of the pictures were very similar, while others were harder to distinguish from one another. The similar images were meant to interfere with memory by mimicking the kind of mundane, day-to-day experiences we have, like locking a door.

The researchers found that the most memorable images were identified as the ones participants were most likely to recall. In the study, they highlight that images that are colorful, feature people or are uncluttered are more memorable.

Yet 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 emotion is typically thought to enhance memory processing, humans tend to remember the "gist" or central aspect of an experience, rather than the extra detail. The passing of time tends to exaggerate this effect, according to the researchers.

For example, when trying to remember what we did last year, we may recall doing lots of different things. However, only a handful of these memories are likely to stand out in great detail. We may remember going on vacation, but we may not remember each day's activities.

The results of the study found that emotional content, time that has passed since the experience and perceptual features of memory all play a key role in whether we remember the details of an event.

"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 in a press statement.

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

Morales-Calva added: "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," she said.

One of the reasons we don't remember everything we experience is because our brains have limited capacity.

"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."

The full findings of the study were published in the journal Neurobiology of Learning and Memory.

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