Our brains are incredibly complex organs, still partly undiscovered, and we hear lots about improving our short-term memory and trying to avoid dementia, but how about our long term memory? After all, it’s where all our knowledge is stored, so shouldn’t we be looking after it, nurturing it, giving it the five-star treatment?
Our thoughts and sensory impressions (such as listening to a speech) initially pass through sensory memory before they reach your short-term or “working” memory, which is where we hold things briefly in mind. A good example of this is remembering phone numbers, car registrations or e-mail addresses. Once information enters your short-term memory, it is permanently encoded in your long-term memory, where it becomes part of your general store of knowledge, although our ability to recall that information is where we all differ from one another.
Exercise your working memory (short-term)
There are many ways of improving your short-term or working memory, and we are not going into that in detail here as it has been well covered in other articles, but just to summarise, diet is important and certain specific super foods can help, exercises which involve memory training, puzzles etc can also help, relaxation and avoiding stress can definitely help, but these are all items covered elsewhere, even on this site.
Long term memory
Let’s look specifically at how we can care for and nurture our long-term memory. Theoretically, the capacity of our long-term memory should be unlimited, the main constraint on recall being accessibility rather than availability. Duration might be a few minutes or a lifetime. Suggested encoding modes are semantic (meaning) and visual (pictorial) in the main but can be acoustic also.
Bahrick et al (1975) investigated what they called very long term memory (VLTM) (1). Nearly 400 participants aged 17 – 74 were tested. Results of the study showed that participants who were tested within 15 years of graduation were about 90% accurate in identifying names and faces. After 48 years they were accurate 80% for verbal and 70% visual. Free recall was worse. After 15 years it was 60% and after 48 years it was 30% accurate.
One of the earliest and most influential distinctions of long-term memory was proposed by Tulving (1972). He proposed a distinction between episodic, semantic and procedural memory.(3)
Procedural memory is a part of the long-term memory is responsible for knowing how to do things, i.e. memory of motor skills. For example, procedural memory would involve knowledge of how to ride a bicycle.
Semantic memory is a part of the long-term memory responsible for storing information about the world. This includes knowledge about the meaning of words, as well as general knowledge. For example, London is the capital of England. It involves conscious thought and is declarative.
Episodic memory is a part of the long-term memory responsible for storing information about events (i.e. episodes) that we have experienced in our lives. It involves conscious thought and is declarative. An example would be a memory of our 1st day at school.
Cohen and Squire (1980) drew a distinction between declarative knowledge and procedural knowledge (2). Procedural knowledge involves “knowing how” to do things but does not involve conscious thought (i.e. it’s unconscious – automatic). For example, we brush our teeth with little or no awareness of the skills involved.
Whereas, declarative knowledge involves “knowing that”, for example, London is the capital of England, zebras are animals, your mom’s birthday etc. Recalling information from declarative memory involves some degree of conscious effort – information is consciously brought to mind and “declared”.
The knowledge that we hold in semantic and episodic memories focuses on “knowing that” something is the case (i.e. declarative). For example, we might have a semantic memory for knowing that Paris is the capital of France, and we might have an episodic memory for knowing that we caught the bus to college today.
Typically, patients suffering from amnesia have great difficulty in retaining episodic and semantic information following the onset of amnesia. Their memory for events and knowledge acquired before the onset of the condition tends to remain intact, but they can’t store new episodic or semantic memories. In other words, it appears that their ability to retain declarative information is impaired.
However, they can recall skills they have already learned (e.g. riding a bike) and acquire new skills (e.g. learning to drive).
Working out your recall
OK, so that is how our long term and short term memory works, in a nutshell, but what can we do to keep our long-term memory in shape? Here are a few tips which should help:
Practice active listening by listening attentively and writing down notes and summaries of concepts, ideas, and facts that are introduced, as well as connections that occur to you from other sources. By taking notes actively, instead of trying to write down everything that was said verbatim, you engage your memory and mind much more deeply.
Develop your own review techniques when reading your notes. Don’t simply read them, but devise a method of association, perhaps when writing; add notes about the weather, the person talking (lecturer, boss, colleague etc), read them out loud. These methods provide you with both repetition and variety; remembering the subject in connection with different acts will create more associations that will enhance your ability to recall information.
Flash cards are a good way of remembering items such as exam revision, speeches or presentations. On one side put the subject you want to memorize, with the name (word, picture, concept) and the answer on the other. I find that simply writing them serves as a great learning technique. If you are studying for an exam or presentation you are giving, practice regularly and frequently.
Keep your brain fuelled. Despite only weighing a few pounds, your brain uses about a quarter of your body’s energy, which means thinking is hard work. Eat regularly, and try to focus on protein and vegetables; fish, green leafy vegetables, and pinto and kidney beans are especially beneficial. Complex carbohydrates like whole grains, lentils, and brown rice give you sustained energy, as well. While you shouldn’t over-indulge, studies indicate that a little caffeine (especially coffee and green tea) or alcohol (particularly red wine) can help your long-term brain health, too.
- Bahrick, H. P., Bahrick, P. O., & Wittinger, R. P. (1975). Fifty years of memory for names and faces: a cross-sectional approach. Journal of Experimental Psychology: General, 104, 54-75.
- Cohen, N. J., & Squire, L. R. (1980). Preserved learning and retention of pattern analyzing skill in amnesia: Dissociation of knowing how and knowing that. Science, 210, 207–209.
- Tulving, E. (1972). Episodic and semantic memory. In E. Tulving & W. Donaldson (Eds.), Organization of Memory, (pp. 381–403). New York: Academic Press.