All you need to know about human memory

All you need to know about human memory

Memory is the process in which information is encoded, stored, and retrieved. Encoding allows information from the outside world to be sensed in the form of chemical and physical stimuli. Memory actually takes many different forms. Patrick Dwyer explains that the kind information and how long we retain it determines what type of memory it is. The biggest categories of memory are short-term memory, working memory, and long-term memory, based on the amount of time the memory is stored and the process.

The scientific study of memory is usually traced back to Hermann Ebbinghaus, who examined his own acquisition and forgetting of new information in the form of series of nonsense syllables tested at various periods up to 31 days. Among many important observations, Ebbinghaus noticed that he often had a first fleeting grasp of the series in moments of special concentration, but that this immediate memory did not ensure that the series had been memorized in a way that would allow its recall later on. Stable memorization sometimes required further repetitions of the series, and if one fails to do so, it could be a learning disability. In 1890, James proposed a distinction between primary memory, the small amount of information held as the trailing edge of the conscious present, and secondary memory, the vast body of knowledge stored over a lifetime. The primary memory of James is like the first fleeting grasp of Ebbinghaus.

Short-term memory

It reflects faculties of the human mind that can hold a limited amount of information in a very accessible state temporarily. It is possible that not every temporarily accessible idea is, or even was, in conscious awareness. For example, by this conception, if you are speaking to a person with a foreign accent and inadvertently alter your speech to match the foreign speaker’s accent, you are influenced by what was until that point an unconscious (and therefore uncontrollable) aspect of your short-term memory. One might relate short-term memory to a pattern of neural firing that represents a particular idea and one might consider the idea to be in short-term memory only when the firing pattern. The individual might or might not be aware of the idea during that period of activation. Short-term memory acts as a kind of “scratch-pad” for temporary recall of the information which is being processed at any point in time, and has been referred to as “the brain’s Post-it note”. It can be thought of as the ability to remember and process information at the same time. It holds a small amount of information (typically around 7 items or even less) in mind in an active, readily-available state for a short period of time (typically from 10 to 15 seconds, or sometimes up to a minute).

Image courtesy of TZA at
Image courtesy of TZA at

Working memory

It includes short-term memory and other processing mechanisms that help to make use of short-term memory, and only to the attention-related aspects of short-term memory. Used to plan and carry out behavior. One relies on working memory to retain the partial results while solving an arithmetic problem without paper, to combine the premises in a lengthy rhetorical argument, or to bake a cake without making the unfortunate mistake of adding the same ingredient twice. The term working memory is often used interchangeably with short-term memory, although technically working memory refers more to the whole theoretical framework of structures and processes used for the temporary storage and manipulation of information, of which short-term memory is just one component.

The working and short-term memory distinction

The distinction between short-term memory and working memory is clouded in a bit of confusion but that is largely the result of different investigators using different definitions. Some refer to temporary memory from a functional standpoint, so from their point of view there is no clear distinction between short-term and working memory.

The short and long-term memory distinction

If there is a difference between short- and long-term memory stores, there are two possible ways in which these stores may differ: in duration, and in capacity. A duration difference means that items in short-term storage decay from this sort of storage as a function of time. A capacity difference means that there is a limit in how many items short-term storage can hold.

Long term memory

Long-Term memories are much more complex than short-term ones. We store different types of information (procedures, life experiences, language, etc.) with separate memory systems. Long-term memory is intended for storage of information over a long period of time. Despite our everyday impressions of forgetting, it seems likely that long-term memory actually decays very little over time, and can store a seemingly unlimited amount of information almost indefinitely. There are different types of Long-Term Memory.

Explicit memory, or declarative memory, is a type of long-term memory requiring conscious thought. It’s what most people have in mind when they think of a memory. Implicit memory is a major form of long-term memory that does not require conscious thought. It allows you to do things by rote. And Autobiographical Memory it the ability to remember parts of our lives. Most of us have one part of life that we remember better than others.