Echoic memory is a type of long term memory which stores information in the form of short term memories. It’s basically a kind of temporary storage system, but it works differently from other types of temporary storage systems. For instance, when you read something on your computer screen or watch TV, those are both forms of temporary storage systems. When you read or watch these things, they’re not storing the information permanently; rather, they’re just temporarily storing it so that you can access it later. However, when you use a flash drive to store files such as music or movies on your computer, the data is stored permanently in the form of temporary memory.
The main difference between permanent and temporary storage systems is how long each type lasts before losing its contents. Permanent storage systems last forever, while temporary storage systems lose their contents over time.
Memory is usually thought of as a way of remembering past events and experiences. There are two major kinds of memory: episodic (or “long-term”) and semantic (or “short-term”). Episodic memory consists of information that’s held in your mind only briefly—for example, the details you remember from a story you’ve heard before. Semantic memory consists of information you remember general facts about, such as your name, the color of your car, and your phone number.
Episodic memory is made up of both semantic and echoic memory. The echoic part is what we’re discussing here. “Echoic” means that memories are preserved in your ears; you can hear, or “echo,” them later. With echoic memory, you can, for example, close your eyes and “hear” music that you’ve listened to before (assuming the music was recorded with vocals or instruments and not just synthesizer noises).
Echoic memory is part of working memory, which also includes short-term memory. Your working memory is the information you’re thinking about at any given moment. It’s something like your brain’s RAM: it allows you to think about a limited amount of information at once. It is the “mental work space” of your mind.
While you’re reading this sentence, you probably aren’t holding a second sentence in your working memory. Instead, the words from the sentence before last are still in your working memory, while the words from this sentence are being transferred to your long-term memory—and at the same time, new words from the sentence after this one are coming into your working memory.
The capacity of your working memory is limited; typically, it can hold between 5 and 9 “slots” of information, with an average of 7 items. However, research has found that this number increases when the information being held in working memory is heavily linked to other knowledge you have. For example, if in addition to the 7 numbers you’re also trying to remember in working memory, you mentally visualize the numbers written on a blackboard, your working memory’s capacity increases to between 9 and 20 “slots”, with an average of 15.
The increase in capacity is due to your previous knowledge—in this case, your knowledge of what a blackboard looks like—spilling over into your working memory. This phenomenon is called the working memory breadth effect.
Your short-term memory is more limited than your long-term memory, although the capacity of both systems varies from person to person. Some people can remember the first several billion digits of pi, while other people can’t remember a phone number long enough to press “call.”
The difference between long-term and short-term memory can be illustrated with the concept of “slippage.” When you try to remember something that’s in your long-term memory but not your short-term memory, there’s a period of time when the information is “slipping” from your long-term to your short-term memory. During this period, you’ll be able to recall the information easily—but only while you’re trying to recall it. After a few minutes, or even seconds, the information will “slip” from your short-term memory and be lost.
The more you use long-term memories, the more they’ll be reinforced in your long-term memory. The same is true for short-term memories: as you recall information from short-term memory to the long-term memory, the memory becomes more stable and less prone to slipping away.
This process is called consolidation. It happens in two ways.
Recent memories are more unstable than older memories. Over time, they become fixed in your mind and no longer “slip.” The second process is called reconsolidation, which refers to the periodic review or re-experiencing of a memory to keep it stable. (This happens on the scale of months for most people).
The “strength” of memories—whether they’re in your long-term or short-term memory—determines how accessible they are.
An active or strong memory is one you’ve thought about recently and one you’ve linked to other memories.
Your memory is considered inaccessible if it’s either very weak (you haven’t thought about it for a long time) or very strong (it’s so important to you that you think about it all the time).
The retrieval of memories is a complex process that depends on the strength of memories and your ability to retrieve the information.
If you have a weak memory, you can sometimes trigger the retrieval of related memories or associations, which can in turn trigger the retrieval of other memories—a process called “retrieval primed recall.”
For example, if you’re given a word stem (“gas_” or “spring_”) and asked to fill in the missing letters and come up with the words “gas” and “spring,” your ability to do this can sometimes trigger the retrieval of long-forgotten memories.
The more cues you have, the easier it is to retrieve a weak memory. For example, if someone tells you that they want to go to the museum for their birthday, you might remember that your parents told you that’s where they went on their first date.
Retrieval practice is when you actively try to recall information from your memory. The more retrieval practice you have with a memory, the more stable and stronger it becomes.
Memory can change over time, both as a result of new information and due to manipulation of information (either intentionally or unintentionally).
For example, if you read in a book that whales are fish, you might initially believe this statement because it comes from a trusted source. The information from the book is now a memory.
If you repeatedly think about this fact and are never presented with contradictory information, it will become very stable in your mind and change from a “memory” that can be changed by new information to a “fact” which you accept as unquestionable truth.
This reinforcement of memories—or misinformation—is called “memory consolidation.” It requires time and lack of contradictory information.
For example, if a friend who knows that whales are mammals points this out to you after you’ve read the book, you might be unsure of what to believe. The memory is destabilized and you’re now able to adjust it with new information.
After some thought (and perhaps discussions with other friends), you might decide that whales might look like fish on the surface, but they’re actually mammals. Your memory of the book has been changed.
Research on memory continues to develop and change as scientific methods grow and improve.
While the ideas about how memory works can seem complex, they have a direct effect on how we learn and understand the world around us.
With a better understanding of how we learn and remember, we can make the most of our ability to take in new information.
We may never be able to easily access long-forgotten memories or learn at the same rate as those with autism and other memory disorders, but we can use techniques to learn in an optimized way.
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