Memory

What is the definition of memory?

In psychology, memory is defined as when we absorb information from the world, process and store that information, and then retrieve that information at a later date. Thus, there are three major components to memory - encoding, storage, and retrieval.

Encoding is when the information we take in from our senses is encoded so that the brain can store that information. Different types of memory use various forms of encoding. For example, short-term memory mainly uses auditory to encode information, such as when you repeat aloud a phone number until you remember it.

Types of Memory

Here we will describe three basic types of memory: sensory memory, short-term memory (STM) and long-term memory (LTM).

Sensory Memory

The senses detect information from the world around us and first enter the sensory memory, which stores a brief impression of the detected stimuli. The sensory stores constantly receive information, but most of this information is not attended to and remains in memory very briefly. It is then replaced with new information. If you pay attention to one of this received information, it enters the STM. The duration of the sensory memory is concise, ¼ to ½ of a second. Sensory memory has different sensory stores for each of the senses to encode the incoming information, so a taste is stored as a taste, a touch is stored as a touch etc.

Short-Term Memory

Short-term memory is the storage of memory available for a short time only (around 30 seconds). Short-term memory can store seven items +/- 2 (so someone's STM might be able to store nine items while another person can store five items). The information to be remembered needs to be continually rehearsed, mainly through mentally repeating or repeating out loud, so that it is not lost from the STM. However, existing information in the STM can be forgotten due to new information coming in. This is known as displacement.

Long-Term Memory (LTM)

The duration and capacity (how much the LTM can store) are unlimited. There are three types of LTM -- episodic, semantic and procedural memory.

Episodic memory is the memory of events in your life. For example, what you did for your sweet 16th, everything you did on holiday in Italy. Episodic memory contains information on what, when and where an event happened.

Semantic memory is the collection of knowledge you have gained throughout your life. For example, the capital of France is Paris.

Procedural memory: procedural memory is your memory of how to do things, such as ride a bike or play the piano.

Fig 1. - Eiffel Tower, knowing that Paris is the capital of France, is an example of semantic memory

Memory Models in Psychology

There are two major models of memory you need to know. They are the multi-store model of memory and the working memory model. A summary of the models will be provided here.

Multi-store Model of Memory

Richard Atkinson and Richard Shiffrin proposed one of the earliest models of memory, the multi-store model of memory (MSM), in 1968. The MSM suggests that there are three separate memory stores. Information is transferred between these three stores in a linear process. The three stores are sensory memory, short-term memory (STM), and long-term memory (LTM). These memory stores differ in how information is encoded, memory storage capacity and how long information is stored (duration).

The senses detect information and first enter the sensory memory. If the information is focused on, it then enters the STM. After that, if the information is given meaning, it then enters the LTM. Information is passed into LTM if given meaning (elaborative rehearsal).

Elaborative rehearsal connects new information in a meaningful way with information already stored in LTM. Elaborative rehearsal is more effective in remembering new information than maintenance rehearsal. Information can be recollected from LTM to STM when needed.

Fig 2. - Multi-store model of memory.

The Working Memory Model

Baddeley and Hitch's (1974) Working Memory Model sought to explain how short-term memory works. The multi-store model of memory suggested that short-term memory was just one single store; however, Baddeley and Hitch thought that short-term memory is more sophisticated, it contains multiple stores and is an actively working memory. The main components in this model are the 'central executive', 'visuospatial sketchpad', 'phonological loop' and 'episodic buffer'.

The central executive is the control centre that all the other components connect to and acts like a control centre. A visuospatial sketchpad is our ability temporarily to hold visual and spatial information. An example of our visuospatial sketchpad is remembering the location of where you left your school books.

A Phonological loop processes speech or verbal information. The phonological loop has two parts, a phonological store that holds verbal information and an articulatory loop which uses inner speech (mental rehearsal) to remember and retain the information in the phonological store.

The episodic buffer blends together information from the three other components (central executive, visuospatial sketchpad and phonological loop) and long-term memory.

Fig 3. Working memory model

Memory Issues

This section below will introduce two explanations for forgetting in psychology: interference and retrieval failure. Both explanations will be further discussed and will be critically evaluated with research evidence in other articles.

Interference

The interference theory of forgetting explains the reason for forgetting in long-term memory. According to interference theory, forgetting happens when memories interfere with and disturb one another. In other words, forgetting occurs when two pieces of information conflict.

Retrieval failure

The retrieval failure theory of forgetting, also known as cue-dependent forgetting, explains the failure to recall information without memory cues. When information is first stored in memory, accompanying signals are also stored. If these cues are not there at the time of recall, you may be unable to recall information in your memory.

Tips on how to improve your memory:

• Focus on the task at hand: when we focus and pay attention to something, it gets transferred from the STM to the LTM. When studying, try to study in a quiet place without any distractions.
• Do not cram information: taking in information regularly over a period of time is better than trying to cram information into the brain in a short space of time.
• Chunking: categorize what you need to learn into different compartments - organize information by grouping related concepts or topics together.
• Make use of learning techniques - try to find ways that will help you to remember, such as coming up with acronyms to help you to remember important points. For example, OCEAN is an acronym for the big 5 personality traits (openness, conscientiousness, extraversion, agreeableness, and neuroticism).
• Relate the information to you: ask yourself how can you connect what you are learning to yourself. When we give information meaning this is called elaborative rehearsal which is how information from the STM gets transferred to the LTM.
• Test yourself: when you test yourself on what you have learned you will learn more effectively than just memorizing something over and over (use our handy flashcards to test yourself!)
• Make associations between new and old information: when you are trying to learn something new, try to think of how it relates to what you already know.
• Visual cues: create graphs and charts to help you to remember information, such as the memory model charts in this explanation!
• Write not type: when we write down information by hand we remember it much better than when we type it. This is because as writing by hand takes longer, we naturally be more selective as to what we write down, focusing only on the main points to be learned.
• Say information aloud: when we read out information to ourselves the actions of speaking and hearing ourselves help the information to be transferred to the LTM.