Introduction
This is the third part of a study of these two articles.
What are the differences between long-term, short-term, and working memory? By Nelson Cowan
50 years of research sparked by Atkinson and Shiffrin (1968) By Kenneth J. Malmberg & Jeroen G. W. Raaijmakers & Richard M. Shiffrin
Context
Capacity is the second limit of our short term memory.
In conditions of free recall or longer lists (≈ larger amounts of information), capacity will be the dominant limiting factor.
Our short term memory is a way of keeping information so that it can be needed immediately.
This can only be done for a limited amount of information.
One example of this is the magical number 7+/-2
7+/-2
This amount was used as a representation of how many different items or ideas could be kept in ones mind at the same time
However, George A. Miller, the psychologist behind this number, revealed it was more of a way to explain his ideas than a well studied result
Recent studies have shown 3 or 4 to be more realistic.
For example, studies have shown :
- 7 item lists usually are remembered with some errors
3 item lists are mostly recalled without any mistakes
- Retrieval of information ( from long term memory) is usually done in blocks of 3s
This capacity isn’t the same with every person or situation.
In adults, this number generally varies between 2 and 6.
It was found to be related to cognitive abilities, thus people with high cognitive abilities will be able to retain a bit more than people with lower abilities.
Information can also be subject of chunking
Chunking ( grouping )
= when similar or related information are remembered together
At first glance, this seems as a way to increase the “magical number”.
However, chunking needs items to be put into awareness multiple times to be compared.
The problem is that this is also a form of rehearsal.
Ways of preventing rehearsal from this perspective are :
- Rapid presentation of the items
- Presenting the items in a perceivable manner without having the participants pay attention to them
Different senses
Everyday information doesn’t comes in a single sense. It is multimodal.
Multimodal
= contains information of several modalities/senses ( touch, smell, taste, auditory, visual…)
Interference
An item perceived in a sense can cause interference for information in another. However, the interfering effect is stronger if they are of the same sense.
This means : a sound will interfere with the retention of a sound more than that of an image.
Storage
The relation of storage of information and senses is strongly impacted by attention.
When paying attention to both senses of bimodal information,
The retention for each aspect of the item measured individually is worsened.
Bimodal
= contains information from two senses
The total amount of information stored, from all modalities involved, cannot be greater than the capacity of one of the involved modalities with the largest capacity.
Next part : Why do we need systems of memory?
First part : Memory, from fractions of a second to an eternity. Also is memory = intelligence?
Second part : When does short term memory become long term?
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