Unlearning and forgetting are crucial for mental acuity

Especially in the elderly, too many memories can cause cluttered path to recall.

To remember well, you have to efficiently retrieve a memory from your brain. But what if that memory comes with lots of baggage or clutter? That’s what researchers believe is happening when healthy older adults try to recall information, but have a harder time doing it than younger people. If the thing you want to remember is stuck to many irrelevant things, thus forcing you to sift through them all - this added work slows down memory performance. Those extra pieces of information can interfere with your ability to quickly remember the target information. And older adults can get distracted by competing thoughts. Their memories may contain irrelevant information that passed through a ‘leaky’ attentional filter.

Forgetting is part of normal brain function due to the limited capacity of the brain. But what is forgotten doesn't completely go away and can be reactivated with a kind of jump start. The memory and the learning just become harder to access during the forgetting process but remain in some form:

Using the aversive olfactory learning of pathogenic bacteria in C. elegans, we show that forgetting generates a novel state of the nervous system that is distinct from the naive state or the learned state. A transient exposure to the training condition or training odorants reactivates this novel state to elicit the previously learned behavior. An AMPA receptor and a type II serotonin receptor act in the central neuron of the learning circuit to decrease and increase the speed to reach this novel state, respectively. - He Liu et al

In a past newsletter [Google Brain] I discussed data that showed our brains will NOT encode and remember information that it knows can be found easily online or archived. [Perhaps, to reduce this problem of clutter?] A recent study using photos confirms this; we use the camera as an external memory device.

The researchers conducted a series of experiments involving 525 participants, who were shown various pieces of artwork, including paintings, sketches and photographs. They were asked to photograph some of the pieces of art using a camera phone, while just observing others. Testing covered five visits; overall data showed photographed art was remembered more poorly than art that was just viewed, after both a short (20 minutes) and long (48 hours) delay between viewing and recall. Taking photos impaired recall of the artwork's details. People were better at recalling their details when they hadn't been taking snaps.

PTSD treatment needs forgetting too - this time emotional unlearning. Here, the game Tetris comes to the rescue, to knock out trigger cues.

Memory of a traumatic event becomes consolidated within hours. Intrusive memories can then flash back repeatedly into the mind’s eye and cause distress. We investigated whether reconsolidation—the process during which memories become malleable when recalled—can be blocked using a cognitive task and whether such an approach can reduce these unbidden intrusions. We predicted that reconsolidation of a reactivated visual memory of experimental trauma could be disrupted by engaging in a visuospatial task that would compete for visual working memory resources. We showed that intrusive memories were virtually abolished by playing the computer game Tetris following a memory-reactivation task 24 hr after initial exposure to experimental trauma. Furthermore, both memory reactivation and playing Tetris were required to reduce subsequent intrusions (Experiment 2), consistent with reconsolidation-update mechanisms. A simple, noninvasive cognitive-task procedure administered after emotional memory has already consolidated (i.e., > 24 hours after exposure to experimental trauma) may prevent the recurrence of intrusive memories of those emotional events. - EL James et al

Results from Experiment 2: mean number of intrusive memories recorded in the diary during thefirst 24 hr following viewing of the experimental trauma film (i.e., preintervention; a), mean number of intrusive memories recorded in the diary across totaled over the 7-day period after the intervention (b),and mean score on the intrusion-provocation task on Day 7 (c). In each graph, results are shown separately for the four groups. Asterisks indicate that results for the reactivation-plus-Tetris group were significantly different from results for the other three groups

All that extra diverse information / associations that Boomers carry in their brains can have a benefit though; it can help them with tasks that require creativity and other open-ended work [like composing newsletters]. Decision-making, too, benefits from an enriched memory.

Personally, I just love it whenever I get the Jeopardy questions before all those young whippersnappers!

“My existence led by confusion boats, mutiny from stern to bow. Ah, but I was so much older then, I'm younger than that now”

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REFERENCES

Energy Efficient Brain = Intelligence biomedworks.substack.com/p/energy-efficient-brain-intelligence

Google Brain. biomedworks.substack.com/p/google-brain

T Amer et al. Cluttered memory representations shape cognition in old age. Trends in Cognitive Sciences. Review| Volume 26, ISSUE 3, P255-267, March 01, 2022. DOI:https://doi.org/10.1016/j.tics.2021.12.002

He Liu et al, Forgetting generates a novel state that is reactivatable, Science Advances (2022). DOI: 10.1126/sciadv.abi9071

Lurie, R., & Westerman, D. L. (2021). Photo-taking impairs memory on perceptual and conceptual memory tests. Journal of Applied Research in Memory and Cognition, 10(2), 289–297. https://doi.org/10.1016/j.jarmac.2020.11.002

EL James et al. Computer Game Play Reduces Intrusive Memories of Experimental Trauma via Reconsolidation-Update Mechanisms. Psychological Science 2015, Vol. 26(8) 1201–1215. DOI: 10.1177/0956797615583071

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