Memory Is More Than It Seems

Source: Photo by Joshua Hoehne on Unsplash

by Peyton Zarate

When you think about memory, images of people, places, and events likely come to mind. Memory is crucial to telling stories, studying for tests, and finding your way home. But it turns out our memories play a big role in doing a myriad of other tasks you might not have realized involved our memory systems.

1. Understanding Language and Words

Every time we read, write, speak, or communicate with others we use our memories. The reason we understand the meaning of any word or phrase is that it is stored in and retrieved from our semantic memory—a type of long-term memory responsible for factual knowledge like the name of the first president of the United States or the object named by the word apple. Semantic memories often arise from multiple learning experiences.

For example, you may have heard the word money in first grade while playing Monopoly for the first time with your family. If this is a happy (or frustrating) memory, or one with strong social relevance, it will be tagged so that it can be easily retrieved in the future (Budson & Kensinger, 2023). So, when you start learning how to count coins in math class and hear the word money again, your brain would likely take you back to the Monopoly game. You might recall where you were sitting, what character you picked, and, most importantly, how your mother explained the word money. Now, linking your mom’s definition to the coins you are counting, your brain has deepened your understanding of money. After hearing money 3, 6, or 10 more times, your brain likely no longer goes back to the vivid image of the Monopoly game to understand the word; it just knows the general definition of money (Budson & Kensinger, 2023). This is how a semantic memory is created.

As you’re reading this post, you can thank your semantic memory—built from many earlier life experiences—for your ability to understand the words and concepts.

Photo by Joshua Hoehne on Unsplash

2. Imagining Fake and Future Scenarios

If someone asked you to imagine yourself on the beach, what would you see? Can you smell the salty water, feel the sand underneath your feet, or hear the crashing waves? Our memories play a crucial role in imagining scenarios like this.

Using an fMRI, which measures activity in different brain regions, studies have shown that parts of the brain used to recall memories are similar to the parts activated when imagining a future scenario (Biderman & Shohamy, 2020). This is because we often use memories from past experiences or knowledge— a prior beach vacation, or a scene from a movie–to imagine ourselves in future scenarios.

Unfortunately, this means that people with memory loss struggle to picture detailed scenarios. Many amnesic patients have suffered damage to their hippocampus, a part of the brain crucial to storing and retrieving long-term memories, as well as imagining future or made-up scenarios (Biderman & Shohamy, 2020). As demonstrated by a study in the United Kingdom, amnesic patients struggled to imagine a vivid scenario, such as laying on the beach, and listed significantly fewer details than those without hippocampal damage (Hassabis et al., 2007).

Similarly, individuals with depression also struggle to imagine specific future scenarios. Previous studies have shown that people with depression were unable to recall specific memories, especially those associated with positive emotions (Williams, 1996). Individuals with depression also struggled to imagine descriptive, non-general future scenarios, such as what one plans to do that weekend, how they plan on getting there, and when they plan on leaving (Williams et al., 1996). Knowing that people with depression are unable to access positive memories and, therefore, struggle to imagine a hope-filled future helps contextualize the fact that most depressed and suicidal individuals share a sense of hopelessness (Salter & Platt, 1990). But, understanding the role that memories (or the lack thereof) play in imagining specific future or made-up scenarios is also key to informing and improving clinical practices.

3. Using Online Calendars and Reminders

If you use online calendars and electronic reminders to keep track of future events, so you don’t have to remember them, you’re using what is called intention offloading. While the purpose of intention offloading is to avoid using our memories to remember the specifics of what we need to do, we still use our memories to keep track of the fact that we set a reminder. You still have to remember to check your calendar and to look at your to-do list.

When it comes to remembering to do something in the future—like going to the store to buy milk—the medial prefrontal cortex (PFC) is responsible for storing the details—like the fact that you need to buy milk—while the lateral PFC is responsible for remembering that you have to do something—like that you needed to go to the store (Gilbert 2011). According to a study that used fMRI (functional magnetic resonance imaging), when people set an external reminder about something, activity in the medial PFC (responsible for the details) stopped, but the activity in the lateral PFC (responsible for remembering there is a reminder) remained steady (Gilbert, 2015). This means that when we use an external tool like Google Calendar, our brains don’t use any energy to remember the content of the reminder, but we still use our brains to remember that we will have to do something in the future.

The great thing about intention offloading is that it is a very reliable and efficient way to use our memories. In the same study, when participants were asked to remember to do something in the future without an external reminder, activity in the Lateral PFC increased while activity in the Medial PFC actually decreased (Gilbert, 2015). This means the brain spends less energy on remembering what we need to do and more energy on remembering the fact that there is something we need to do—which is why you will drive to the store, walk in, and immediately forget that you needed to buy milk. In another study by Gilbert et al. (2020), participants’ forgetting rate when only using their memory was 45% while the forgetting rate when using external reminders was 5%—highlighting the efficacy of intention offloading.

Memory Essential Reads

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How to Hold On to Your Best Memories

Because our brains can only hold so much information at once, using Google Calendar and other external reminders is an effective and productive use of our memories—even if we think we are not using our memories.

While there is always more to uncover when it comes to the neuroscience of memory, we have already discovered how memory is crucial to many hidden, but important, everyday tasks.

This post was researched and drafted by Peyton Zarate, under the guidance of Dr. Elizabeth Kensinger.