By Gregory Kellett, a cognitive neuroscience researcher at SFSU and UCSF and science writer for Lumos Labs.
Memories are vital to our ability to function on even the most basic of levels. Our respective “realities” are in fact a large part due to the constantly shifting kaleidoscope of our remembrances. Here we will touch briefly on the difference between short-term/working memory and long-term memory as well as how the two filter and add meaning to our worlds.
What if we could remember everything we experienced? As enticing as
it sounds, our finite brains would quickly find themselves overwhelmed with the random details of yesterday’s weather forecast alongside the nutritional information off of last month’s box of raisin bran.
Thankfully, the vast majority of our memories are fleeting mental wisps lasting only seconds to minutes. These temporary impressions make up what is called short-term or working memory.
Working memory can be thought of as a staging area where the mind takes meaning from such items as:
- Specific immediate memories of very recent sensory input (IE the sour smell of expired milk).
- The temporary recollection of details from long-term memories (IE what happened the last time you drank sour milk).
- Conclusions and ideas made in the past (Sour milk is bad).
Notice how working memory can temporarily pull details from long-term memory for short-term use. Although
constantly changing and ephemeral itself, working memory is vital to our ability to make decisions and take action over time (such as our pouring that sour milk down the drain). For a brilliant and more in-depth description of working memory read Elizabeth Buchen’s “Working Memory: What it is and how it works”.
When an experience or piece of information sticks and doesn’t evaporate with short-term memory, it is said to have entered into the realm of long-term memory. This journey is called consolidation and takes place after prolonged exposure to a piece of information or experience. The longer the exposure, the better the consolidation, the more robust the related memories will be.
Long-term memories can store much larger quantities of information than working memory and for much longer periods of time (often as much as a lifetime). These resilient long-term recollections are made up of both consciously learned facts, such as “Madrid is the capital of Spain” and subconsciously learned knowledge, such as the ability to balance and ride a bike.
We derive meaning and the ability to act via the synergistic relationship between long-term 
and working memory. Working memory combines elements from our long-term stores with immediate sensory information in order to generate ideas and plans of action. For example, remembering that the taste of peanut butter is pleasant as we toast toast, might just have us use our memorized skill of unscrewing a jar in order to manifest the pleasurable experience of peanut butter on toast. Which is just one more potentially delicious result of a fit and active mind.
16 Comments
Great post! In the spirit of inviting discussion…
=is it really attention that selects things from sensory memory into a short-term store? If so, why wouldn’t training of updating show transfer to all the other situations in which attention is known to be involved (eg., stroop?) Dahlin et al., Science, 2008.
- how do conclusions and ideas enter working memory, along with the details of the experience (whether extracted from sensory or long-term memory)?
- the unavoidable question: what is the relationship between short-term and working memory?
- what causes does the infamous limitation to human working memory ? is it retrieval from LTM, the amount of information that can be consolidated/selected into WM from sensory memory, narrowness of the focus of attention, or some other limitation that gives rise to the new “magic number” 4 +/- 1?
loved the post, and would love a more in-depth follow-up as well…
In the concept of “You are what you eat”, which supplements aid in preventing cognitive decline?
Cheers Chris,
Those are some very big questions.
Let me start by saying that although a lot of research is showing some very interesting results in this area,…not much is established definitively and we still have much to learn (which I have a hunch you already know).
Concerning the role of attention in the selection process,..It does seem to play a very important role in actively finding and maintaining cues for use in updating working memory stores,.. with working memory itself feeding back to influence attention. It is, as you point out, still unclear as to how much attention training can transfer to other attention related situations. This seems to depend, at least in part, on what type of and how attention is targeted. You are probably familiar with some recent research (Jaeggi et al., Proc Natl Acad Sci, 2008) indicating that multi-modal attention training (dual n-back) is capable of producing a robust transfer to measures of fluid intelligence. A lot more research is needed though.
Concerning the relationship between short-term and working memory and how details enter working memory,.. again we don’t really know. The later, however, probably has something to do with Dopamine mediated pre-frontal cortex activity as well as neural resonance within and between various brain regions, with particular emphasis on the Striatum.
And finally, my personal take on what limits working memory is that it mostly depends on attention and how much overlap there exists between the input at hand and any related long-term memory stores that can be drawn upon.
You really know how to work a blogger Chris.
By the way, I’ve recently discovered yours and have been enjoying it very much.
Felix,
We will be posting something precisely along those lines very soon. For now, let me just say that I take fish oil capsules daily.
Hey, I know you! I work for a company across the, er, city. We should chat sometime… good to read your blog, though.
I was looking for MindTweeks and found this web site regarding the long term memory!
Very impressed regarding the insights…
Great share..
Do you think someone who has lost thier long term memory in car accident and has a TBI could re-gain all of the long term memory?
Regards,
Deb
Very nice!!
Hello Deb,
Thanks for the Kudos.
Your inquiry concerning traumatic brain injury and long-term memory is best directed to a neurologist familiar with the case in question.
I am only 37 years old and for at least two to four years I have struggled to recall words. I either say the wrong word–”It’s on the bed” when I mean “It’s on the sofa” Or, I struggle for several seconds to find the word I want to use when I’m in conversation. Often, others just fill in the word for me. Sometimes my words come out slurred because I’ll start the word and not be able to finish it. My profession requires me to talk with people, often large groups of people. I have a master’s degree and I’m a reasonably intelligent person. My writing flows better than my speaking. I’ve not had a stroke, but I did take anti-depressants and stopped taking them abruptly on three or four occassions. Could that be the culprit? Or, is it perimenapause (I’m a female)? Should I go to a speech pathologist? Have you heard of this before? Help!!
Does anyone have an idea as to which function is mostly responsible for the recall of relevant information in a particular stimuli?
Hey, Eddie, I am not a medical professional in any capacity, but I will say that I was on a sequence of SSRIs for nearly two years. The last one, Paxil CR, caused lengthy withdrawal effects for quite a few months. One of the problems I developed, and am still bothered by in some ways, was with my language. There were times where I ended up picking the wrong word while talking about or describing things, but my biggest problem was losing my train of thought repeatedly and trailing off in the middle of sentences. I was reasonably healthy, neurologically, before taking the antidepressants, and able to speak well. I would say talk to your doctor if you ever did decide to take one of those drugs again, but most of them minimize talk of side effects and refuse to believe there can be lingering effects from these meds.
Oh, sorry, I was responding to the person who posted the Ninth Comment.
Hi eddie,
I’m similar to you: female; same age, educated & also have to speak in public at prominent events (to “experts”!). I often struggle to find my word or I make up a similar word to the one I want. I’m very logical but can suddenly lose my train of thought. I over prepare for talks due to fear of this happening. Then I worry I have to speak in a setting where it’s difficult to have notes in front of me. But if you get good feedback that’s the important thing.
Despite these issues, I’m actually good with language, think very clearly & write very well when I try. I figure that there are differences between individuals in language use & recall, so unless I really do go nuts or until I find out I have alzeimers, I don’t really have anything to worry about other than social concern, it’s all ok.
I haven’t been on prescribed anti-depressants but I do struggle with depression & anxiety, then it starts to develop into ‘worry about the worry’ which threatens to compound to infinity & be crippling. I recently found a book I’d recommend: “The Mindful Way through Depression” by Mark Williams, John Teasdale, Zindel Segal & Jon Kabat-Zinn. Get your hands on it and treat it as a work book ie to read, reread & work through for a set period of time. It helps focus on constructive positives, and it blends the best of east & west therapies (which I had started totry to do). It’s full of “ah-ha!” moments
Gregory Kellett, you mention that you take fish oil capsules daily. Are you aware of any problems with PCB’s (or other harmful substances)in these? I’ve purchased some that list sardines and anchovy as the source, and have heard that PCB’s can be an issue with sardines. Thanks.
Hello Jane,
I’m only familiar with one study which looked into the issue of polychlorinated biphenyls (PCB’s) and fish oil.
Out of the 5 mainstream fish oil supplements tested, none proved to have detectable levels of PCBs. This apparently also applies to Mercury.
Eddie, Dan and Nathaniel I sympathize with your problem with words. I suffered this first last September, and losing my words was traumatic. It’s hard to hold a conversation with friends or feel comfortable about what’s happening to you.
Fortunately I found a good geriatrician who put me on aricept and I’m back to myself again, talking a blue streak.
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