I understand that some mental diseases can cause the sufferer to lose their short term, or long term memory. However, what I am wondering is does anyone understand how you can lose one without losing the other? Once you are unable to form short term memories, how do you form long term memories? are the different types of memory formed independently? In general, can anyone give me some insight on what science knows about memory and how it forms?
Thanks for all replies,
AllFree
You’ve already formed __ years worth of long-term memories. If your long-term memory is functional, you will recall them.
Have a look at Wikipedia on short-term memory.
I used to know the answer to this, but I forgot.
(Someone was going to say that eventually)
I’m no expert on memory, but I did work for a neurologist for a while (which is kinda like saying I stayed at a Holiday Inn Express last night as far as my credentials goes).
But anyway-
My understanding of it is that there definitely are two different storage mechanisms going on. You first store memories in short term memory. Then, somehow (I don’t think they know how yet), these memories get sorted through and transferred to long term memory. If you completely lose your ability to form short term memories then you will not form new long term memories from them. However, your existing long term memory will be fine. This is why people who get older and start suffering from dementia have a hard time learning new things but can recall all sorts of earlier things without difficulty. Usually your short term memory just degrades. It is much more rare for it to fail completely.
One interesting thing that we do know is that memories are not stored like how a computer stores information. We don’t just shove it into a box somewhere inside our brain. We break information down into chunks somehow, and store the chunks separately. There was a guy named Kim Peek that was sorta the real life inspiration for Rain Man (a good movie, if you haven’t seen it). While we still don’t understand memories and what gave Kim a lot of his abilities, it seems as though the part of his brain that broke information down and stored it didn’t work properly, so instead of breaking it down and storing it he just stored it. There were certain types of humor and such that he just couldn’t understand. For example, if you said “get a grip on yourself” he couldn’t understand the abstract concept, and only understood it as physically grabbing part of himself. He also had a lot of difficulty with social interactions. Unlike most savants, he was able to develop social skills (probably due in part to the extra attention he received because of Rain Man), but instead of learning how to interact like you and I do, he had to basically memorize different ways of coping with different situations so that he could function. He basically learned a lot of tricks which helped him interact socially despite the fact that his brain really couldn’t properly interact socially with others.
Kim Peek’s wikipedia page:
Another interesting thing about memory and such is that you might think that smarter people use more of their brain. Actually, the opposite is true. When smart people do something, according to brain scans that show brain activity, they do it in a more efficient manner, using less of their brain to accomplish the same task.
Here’s an example. If you show a computer an image of an apple, it has a really hard time breaking down the image and figuring out that it is an apple. Humans on the other hand do this really easily. But if you do a brain scan of a person while showing them an apple, it isn’t like just one part of their brain fires off. There isn’t one “apple” piece of memory in your brain. Instead, all different sorts of things will fire off at once. You might get a section of your brain that always fires off when you see anything round, and another section that fires off when you see something red. Exactly how your brain puts all of this together and you instantly think “apple” isn’t really understood though.
Short term memories and long term memories do activate different sections of your brain, according to brain scan tests.
Don’t have the background on this handy, but people tend to fall into groups of ‘associative’ and ‘relational’ memory, corresponding to the computer database terms (and there might be other neurological science terms as well). Relational memory is more like retaining one-to-one connections between things like words and definitions, while associative memory does better at keeping similar things grouped together. There are arguments about which is more efficient at speed, accuracy, or volume.
My view of this area may be skewed because I consider brains to be computers with poor operating system design, at least in the area of memory. When it comes to pattern matching, extrapolation, and other high end functions, it beats UNIX all to hell.
I have a question based on this article if anyone knows. It says there appears to be a limit of the number of simultaneous short term memories that can be stored at one time of around 9, with a common limit of 7 +/-2 being accepted. It also states that short term memory is of very short duration, on the order of seconds. Am I correct in assuming that if more than a certain number of memorable events (no-matter how memorable) occur within a short span of time, it will overload my short term memory and I will literally be incapable of remember something very notable?
If they were all equally memorable, you would probably start to forget some of them. Usually with the 7-9 rule, people tend to use the example of a phone number. That’s 7 digits right there- the perfect lil’ amount to remember in your short term memory. So if you’re forced to memorize things, it’s often easier to break them down into smaller chunks (like taking larger strings of numbers and breaking them down into double digit numbers and such to help recall them).
That said, you will also be updating your priorities as you start to slip- so if you’re given a list of 7-10 terms and told to recall them 3-5 mins later, people often will use lil’ things like associations or repetition of certain key phrases to remember the ones “more important” to them.
The key is the phrasing “memorable events”- not so much the sense of 7-9 “events” as in actions or happenings or such, but more likely, 7-9 pieces of information. Like if you scan the road ahead of you while driving for the next 10 mins- are you likely to remember each and every car that passes you, and their license plates? Probably not. But you might remember the one funny plate that was a pun, or you might recall that you stopped at 3 red lights in a row or such. Attaching emotional significance to events can also help you recall them a little bit better (which is why they say that the limbic system is involved in memory consolidation and such).
So it’s LESS likely you’re going to forget something you place of high value if you can keep it significant (the funny car license plate vs. all the other ones you saw that day), but it’s certainly possible after a few days that you won’t even recall the original funny plate because it was only in your short term memory and never consolidated or reinforced.
I recall an old parlor trick. Show someone(s) a set of 3 symbols for a few seconds, like %^&. Then wait 30 seconds and see if they can recall them. Usually they will for just 3 symbols. Numbers work just as well. Show them larger sets of symbols in the same manner while explaining how people can usually remember a string of 5-10 symbols, but it gets much harder as the number gets higher. When the string gets above 10 symbols, they will start doing poorly, but then tell them the next set has more than 20 different symbols, but they will have no trouble rememebering them in the correct order.
ABCDEFGHIJKLMNOPQRSTUVWXYZ
Also, when the 9 digit zip code was introduced, some people claimed that was too many digits to remember, but the post office said they only had to remember 5 things, the zip code they already new, plus 4 new digits.
I think the most basic answer to your question is that short- and long-term memories are stored in different parts of the brain. So if one gets damaged, it does not necessarily negate the other.
The ability of the brain to work around damage is largely dependent upon many factors, such as the amount of damage, the age of the brain, and the strength of the neural pathways in and around the damaged area. Strong neural pathways are formed by repetition–repeated use of the pathway literally puts extra sheathing, or coating, around the neurons in that pathway. Make that pathway strong enough, and that short-term memory will at some point get transferred to your long-term memory. Use that particular long-term memory enough, and those neural pathways will be strengthened, allowing easy recall of the event/information. Engaging different parts of your brain (by learning different things) also helps create pathways that can aid in damage work-arounds. (This process is one of the ways people avoid dementia when they get older)
More memory trivia: all memory is tied to emotion. If I could pop open your brain and examine every long-term memory you have, they’d all have associated emotions. When people experience large events in life, there’s usually strong emotion tied with them. This is sort of a mental quilt upon which specific event-based memories are stitched. To try and answer AllFreedomUnlessDefyingScience’s question, I think it all depends on the circumstances. I don’t think there are multiple events that could happen quickly enough to overwhelm the (otherwise healthy and unimpaired) brain to the point where general events are dropped. What would wind up happening is some amount of detail may not make it, but the general event, assuming there is a large emotional component, would.
I recall this “phone number” example being trotted out to confirm the phenomenon in my Psych classes at college 20+ years ago, but in one of my Advertising classes it was given a different twist: the professor claimed that it applies to direct-marketing mailers as well. According to him, it’s precisely why all of those unsolicited offers for credit cards, real estate, and magazine subscriptions that arrive in the mail have 7 (+/-2) pieces in them (cover letter, coupon, brochure, etc.)
However, he never really made a solid case by explaining what, if anything, this has to do with memory. Do I really need to remember all 7 pieces of junk in that envelope to gauge my interest in responding?
If there’s any truth to it, marketers must think our collective short-term memories have gotten better over the years, because I’ve noticed those mailers have an increased tendency to choke my shredder nowadays. (Hey, come to think of it, a lot of metro areas have instituted 10-digit dialing since my college days too… maybe there’s something to this.)
The same professor said that it applies to billboard copy as well, i.e. that the most effective billboards you see while driving are those with seven or fewer words on them. This one I can believe, although it probably has more to do with font size and simple legibility at 65mph than short- or long-term memory.
I thought of one entirely plausible situation where you could exceed the number of vitally important events in the time limit of your short term memory: Combat during wartime. While not a veteran myself, based on what I know about combat gleaned from effectively academic (but self-taught) and conversation with a few veterans it should be entirely possible to have more than a dozen things happening at once that are all important, in addition, the same should be true of combat pilots. If so you can be damn sure the military has studied it, does anyone know if they have and if the results are public?
Remember Sammy Jankis.
Combat pilots are, to the best of my knowledge, not very concerned with combat memory performance. One of the main reasons military pilots go through the amount and type of training that they do is because the brain will fall back to those skills and procedures during times of high stress, like dogfighting or emergency procedures. In that sense, I think the memory portion of combat stress (even for the soldier) is still active–you may not be remembering what color the insurgent’s colthes are as he’s shooting at you, but you will remember how to act individually and collectively as a unit in order to defeat that threat.