Summary: The study sheds light on the mechanisms involved in removing information from working memory and concludes that forgetting information requires a lot of effort.
Source: Cognitive Neuroscience Society
Forgetting is not always easy.
If you’ve ever tried to get that pesky earworm out of your mind or stop thinking about whether you locked the door after leaving the house, you know how distracting it can be to think about something unrelated to work. in hand
While much work in cognitive neuroscience has focused on how the human brain remembers and retains information, some cognitive neuroscientists have instead focused on forgetting – working to track exactly how we forget a piece of information and what what this means for patients suffering from neurocognitive disorders.
“It can be surprising that people can control what and how they forget,” said Marie Banich of the University of Colorado, Boulder, who led a session on new research on forgetting at the Cognitive Neuroscience Society’s (CNS) annual meeting today in San Francisco.
“But control over working memory is critical for switching between and reprioritizing tasks. So in many ways, it’s not surprising that we have control over the ability to remove information from the focus of our thoughts.”
In the new work presented by Banich and others, the researchers identified unique mechanisms by which people remove information from their working memory and also found that forgetting requires a lot of effort.
“We found that deliberately forgetting irrelevant information from the mind is beneficial, but it doesn’t happen automatically,” said Sara Festini of the University of Tampa, who will also present the new work at the CNS conference.
The hope is that this body of work can lead not only to a better understanding of attention and focus but also to clinical targets for helping patients suffering from disorders ranging from depression to schizophrenia. to PTSD and ADHD.
Tracking the Loss of a Mind
Banich became interested in understanding forgetting after losing someone to suicide. The experience made him think about the dangers of intrusive thoughts for people suffering from depression and related disorders.
“The content that remains in the mind varies in different disorders,” Banich explains.
For example, people with schizophrenia may have paranoid thoughts, while those with obsessive-compulsive disorder may worry about germs, and a person with anxiety may stop thinking about bad things that may happen in the future.
“But it’s the same process,” he said. “Thoughts swirl around, become the focus of attention and are hard to get rid of.”
Complicating the treatment of these disorders is the fact that there is so much reliance on self-reporting of symptoms, and even when a patient reports improvement, they may still be thinking negatively.
That challenge led Banich, a trained cognitive neuroscientist, down a path to answer the question: How do we know when someone has truly stopped thinking about something?
Step by step, Banich and his colleagues learn how to track what happens when a person tries to get a thought out of their mind. Their latest work builds on their previous peer-reviewed work that documented three neurologically distinct ways people remove information from their working memory: replacing a thought with something else, inhibiting that thought , or emptying their minds of all thoughts.
This seemingly simple framework took years of work, aided by fMRI imaging, machine learning, and other technological and experimental advances. It started, Banich says, with the realization in the middle of the night that “we can actually use neuroimaging to verify that someone has stopped thinking about something.”
Asking participants to think about information in different categories (e.g. faces, places, fruit) while in an fMRI scanner, Banich and his team first trained a computer on the resulting neural patterns for categories and examples from each. They then asked study participants to forget information in different categories, verifying whether it had been removed by tracking whether the brain pattern was still present.
They also identified the neural pattern of brain activation associated with each of the three forgetting mechanisms – whether they replaced the thought of a face like Emma Watson, with an object, like the Golden Gate Bridge, prevented Emma Watson’s memory, or cleared all thoughts.
Through this work, they identified four brain networks that clearly activate whether a memory is retained or purged through one of three mechanisms: the somatomotor network, the visual network, the default mode network, and the frontoparietal control network.
Their work suggests that when the brain suppresses a thought or clears thoughts entirely, the frontoparietal control network likely plays a prominent and unique role.
By identifying these specific brain networks, the research offers a path for investigating potential differences among individuals in how they forget.
“Can we get some measure of people who may have difficulty controlling their thoughts?” Banich asked.
“Maybe the frontoparietal network in people who have trouble controlling their thoughts can’t distinguish between those mechanisms, or are they all confused?”
In future work, Banich and his colleagues will also see if they can use biofeedback while the participants are in the fMRI scanner to see if that can help individuals control the mechanism for removing unwanted information.
Putting in the Effort to Forget
An important part of this work looks at “proactive interference,” which can occur when the brain tries to learn something new that overlaps with a category already in mind — like trying to learn Emma Stone’s face instead of Emma’s Watson. The takeaway from Banich’s work is that, in part because of proactive interference, suppressing a thought is better than replacing it.
In fact in work by Sara Festini and colleagues presented in San Francisco, researchers found that one benefit of voluntarily forgetting a piece of information is that it reduces proactive interference – making it easier for a person to learn. a new one.
“Proactive interference happens, for example, when you accidentally go where you parked your car yesterday instead of where you parked your car today,” Festini said.
“We show that by voluntarily removing information from working memory, it makes the information less susceptible to harmful forms of memory interference, such as false memories and proactive interference.”
In Festini’s studies, researchers, following an established paradigm, teach their participants to forget through explicit instructions that include a “forget cue.” These clues, he says, aren’t just a lab trick. In real life, there might be a forget cue when taking drive-thru orders: if someone changes an order, they might say “Oh, never mind! I don’t want that anymore.” Or in class, an instructor may tell their students to ignore a previous statement, if it is inaccurate or no longer relevant.
Evidence from Festini’s lab suggests not only that these forget cues work but that they promote the goal-directed removal of information from working memory in a “different—and more useful” process. -advantages rather than—simply reduced information processing,” he said.
“We also have evidence that other attention-demanding tasks can interfere with the efficiency of directed forgetting within working memory.” That makes the process of forgetting effortful and different from simply ceasing to process information, echoing some of Banich’s work.
In other studies, Festini and his colleagues found that directed forgetting in older adults is impaired compared to younger adults, but that implicit forgetting cues can still help reduce the working memory impairment for both younger and older adults.
Although Festini’s team’s research did not specifically examine clinical applications, it suggests that voluntarily removing information from working memory may be more difficult for individuals with major depressive disorder or ADHD. , for example.
Banich also speculated about how the body of work could help in understanding and treating PTSD, noting that people with PTSD tend to overgeneralize memories (e.g. when a backfiring vehicle can trigger the memory of an explosion).
Because the process of forgetting appears to be laborious and works best when specifically targeted, those with PTSD may have challenges identifying and then suppressing specific memory.
“There’s a paradoxical effect that if you’re told to stop thinking about something, you actually have to recognize and think about it to suppress it,” he says.
Currently, Festini is conducting a new study of how and when people remove information from working memory that is designated as unimportant or less important, without being given specific “forgetting” instructions.
“I’m curious to understand what the tipping point is to motivate someone to engage in the effortful removal of information from working memory,” he says, “because there are clear benefits to removing less important information, but this withdrawal process is focused on attention. demanding.”
About this memory research news
Author: Lisa MP Munoz
Source: Cognitive Neuroscience Society
Contact: Lisa MP Munoz – Cognitive Neuroscience Society
Image: The image is in the public domain
Original Research: The findings will be presented at the Cognitive Neuroscience Society 30th Annual Meeting