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One of the widest held explanations of how memory operates, is that impulses from
different areas of the brain and from the senses, enter the limbic system (situated in the central area of the brain), and are then passed through the mamillary body. These memory impulses then travel around the fornix, to terminate at the hypocampus and the cingulate gyrus.
These limbic structures are the ones that it would seem are responsible for the recording and the retrieval of memories. It also has been found, that damage to these structures is the cause of many of the more acute forms of amnesia.
Learning curves
A useful phenomenon to understand as a prelude to mnemonics, is that of learning curves. These are best explained with the aid of a diagram.
Basically what the above diagram illustrates, is that information studied at the beginning and at the end of a study period, is far more readily recalled than is information studied in the middle.
This phenomenon can be explained by the Primacy and the Recency effects. I will now proceed to go into a little more detail regarding the exact significance of these two effects.
Primacy and Recency effects
It has been noted in several studies, such as those conducted by Ley in 1972 and Ley, Bradshaw, Eaves and Walker in 1973, that when important information is presented to subjects at the beginning of a study period, it is far more readily recalled than information from the middle of the same study period.
This phenomenon, which is known as the Primacy effect, is very useful to keep in mind when studying for exams, or when trying to recall any large quantity of information.
Other observers have also noted that information from the end of a particular study period is also recalled far more readily than that from the middle. The Recency effect.
Through further research, it has been found that the optimum period of time for memory or information formation, is the first and last ten minutes of any study period.
From the above example learning curve and from the previously defined Primacy and Recency effects, we may conclude that it is better when attempting to study, to divide your study period into several small and easily manageable segments. Say of around about twenty minutes or so each. These should be followed by a break of approximately five to ten minutes. This is so that you can allow your mind a chance to pause.
Studying in this way, you should find that you are able to absorb more information and will be able to recollect it far more readily than you can using more traditional cramming techniques. By the way, the peaks in the middle of the diagram represent information that is familiar in some way, or that for some reason stands out from the rest of the text being studied. This kind of information grabs the reader’s attention, and as a result is more readily absorbed and recalled than the information contained in the rest of the text.
State dependent learning
A study by a psychologist called Overton in 1972, showed that people under the influence of alcohol, could recall events that they had experienced whilst in a similar state of inebriation, far more readily than they could when they were sober.
What may be concluded from this study, is that individuals are able to recall information or events that they experienced whilst in a certain physiological state, far more easily when they are once again in such a state.
This also seems to be true for a number of other drugs, besides alcohol. Such as various Amphetamines and Barbiturates. Certain emotional states also appear to play a role in recollection. Collectively this phenomenon is known as ‘State dependent learning.’
State dependent learning seems to operate by providing a context for information to be remembered in. And a number of studies have shown that the context that we set our memories in, is indeed very important with regards to their subsequent retrieval.
An example of this, would be the way in which hearing a particular song can in some cases bring forth a whole set of memories to an individual.
This phenomenon occurs because the song is a part of the context that the memories were recorded in. Specifically the song in the above analogy, is a part of the ‘external context.’ Whilst the alcohol in Overton’s study, is a part of the ‘internal context.’
Context is the most important aspect of memory formation. This is because it is the context that forms the chain, which links together memories (or pieces of information), which might otherwise seem unrelated to each other. And it is this linking together of memories, or groups of memories, that lies at the very heart of all of the major memory improvement systems that will be outlined throughout the course of this book.