How does Memory Work?
Every human being relies on the ability to store, retain and retrieve information; this process is facilitated by the memory. Human memory, while taken for granted by practically everyone, is essentially related to how our brain works. The brain is an extremely complex and mysterious structure. Even today, we know very little about all of our brain’s functions. While our knowledge of memory is relatively little, there are many theories about specific parts of our brain that most scientists and researchers believe are important to human memory. The study of memory is an interdisciplinary approach studied by both neuro-biologists and psychologists. This study is sometimes called the study of cognitive psychology.
The Main Processes of Memory
Memory relies on three important abilities: The ability to store information or stimuli, the ability to retain this information and the ability of the brain to retrieve it. In cognitive psychology, these are termed are encoding, storage and retrieval.
Obviously, the ability of the brain to process memory is extremely vital and essential to human beings and for that matter all organisms. It gives an organism a very important tool to survive, by remembering where to find food, where predators could be, and where one’s shelter is located.
Types of Memory
While memory is usually characterized as having only three processes, there are many forms of memory that we all experience on a daily basis. These memories can be classified by the amount of time that each memory ca retain information. They include:
Sensory Memory – Sensory memory is the most basic type of memory because it lasts about a split second (200-500 milliseconds). For instance, when you look at an apple, you know that you are looking at an apple and you can see that the apple is red. You don’t stare at an apple and realize every second that you see a new apple. Sensory memory is extremely important, but for more complex organisms such as humans, we need to be able to retain information or stimuli for much longer periods of time.
Short Term Memory – Short term memory is similar to sensory memory, except that the duration that one can hold and retain information is much longer, usually from a few seconds to a minute with rehearsal (rehearsal in this instance means when a person makes an effort to retain information for a longer period of time).
A good description of short term memory is when someone recites a phone number for you to dial. In most cases, you can remember the phone number for a few seconds, but usually not longer than one minute. In fact, many people have difficulties even remembering a 7 digit telephone number. The amount of items that one can retain in short term memory without rehearsal is usually about 4 to 7 items. So this is the reason why, many times when someone recites a telephone number for you to dial, you usually have to ask the person to say it again or write it down.
It should be noted that there are ways to increase the amount of items that we can remember using short term memory. This process is called chunking. For instance, when trying to remember a phone number, we will chunk the first three numbers together and then the last four numbers together. If someone said 345 and 8589, many will find it easier to remember than one large number such as 3458589.
Long Term Memory – Long term memory is extremely important and to many people is what makes them who they are. While sensory memory only lasts a split second and short term memory generally lasts less than a minute, long term memory has the ability to last an entire lifetime. What makes long term memory even more powerful is that the amount of information that one can retain is usually limitless, with rehearsal such as studying or practicing a task, one can easily retain complex information for very long periods of time.
Other Types of Memory
Besides sensory, short term and long term memory, there are other ways to classify memory. One way is to classify it by information type. Under information types, memory can be divided into declarative memory and procedural memory.
Declarative memory is a type of long term memory that requires conscious recall of stored information. Many times declarative memory is called explicit memory, because the person explicitly stores these memories in order to retrieve them later (e.g. studying dates for a history test). Furthermore, declarative memory can be divided into semantic and episodic memory. Semantic memory relates to memories such as dates that can be recalled, while episodic memory are memories that are encoded with abstract knowledge, like personal memories of events, such as your birthday party when you were six years old, or recalling what a rose smells like.
Procedural memory, sometimes called implicit memory is that form of memory which is not consciously retrieved, but what you specifically learn. For instance, when you first learn to ride a bicycle you might be wobbly and fall. While you might be conscious at first learning how to ride a bicycle, after a while, you automatically get better, because you are implicitly learning. With implicit memory, we are unconsciously accessing previous memories and experiences and building upon that knowledge to become better at a task.
The Physiology of Memory
It should be noted that currently science does not know fully just how memories are stored. Although the exact ways of how memories are processed, stored or retrieved are unknown, most scientists do know which parts of the brain are involved. They include the hippocampus, the amygdale and or the mamillary bodies. One of the means by which scientists have got to know that these parts of the brain are partially responsible for memory is that when an injury occurs to these parts, the person becomes deficient in either processing, storing or retrieving memories.
How Memory Works – Possible Theories
Although science does not know for sure exactly how memories are physically stored, there are several prominent theories available. They include the ‘Multi-Store Theory’ by Atkinson and Shiffrin and ‘Levels of Processing Theory’ by Craig and Lockhart.
Multi-Store Theory
While very basic, this theory does a good job of explaining how simple stimuli become short term and long term memories. In multi-store memory, in order to change a simple sensory stimuli that lasts a split second into a short term memory, the person must pay attention to the stimuli that he or she is experiencing. This turns a sensory memory into a short term memory.
If the person wants to turn a short term memory into a long term memory, the person must rehearse the short term memory, i.e. make an effort to retain information for a longer period of time. While extremely basic, it explains how many sensory memories can turn into long term memories, but the disadvantage of this theory is that many of our memories are retained for long periods of time without paying attention or going through rehearsal.
Levels of Processing Theory
In this theory, instead of using rehearsal or paying attention to stimuli to create memories, it is the amount and depth of processing that can have an effect on stimuli which forms long term memory. Processing can come in many forms, such as organizing information, distinguishing information from other stimuli and the amount of effort one puts into trying to retrieve memories. This theory has been researched and has shown some significance. However, there are still many unanswered questions regarding this theory.
The science of memories is still in its infancy. However, new discoveries and insights are being made every year. Since memories are so important and vital not only to our personal life, but also in business and education, much more animated research will continue.