Seven, plus or minus two
From unthinkMedia
Millar makes a distinction that the “amount of information” share commonalities with “variance”. Keeping this in a discrete statistical distribution, it allows for an examination of information retention in situations where metrics are not ordinarily considered
“When we have a large variance, we are very ignorant about what is going to happen. If we are very ignorant, then when we make the observation it gives us a lot of information. On the other hand, if the variance is very small, we know in advance how our observation must come out, so we get little information from making the observation” (p.82).
He states that in order to measure the correlation between input and output, we could identify how much of the output variance is attributable to the input and how much is due to "random fluctuations or 'noise' introduced by the system during transmission." In this example the:
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Channel Capacity
This concept based on the idea that information has to pass through a limited capacity in order to be processed by the observer. Essential this "channel" acts as a bottleneck. A way of visualizing it for me would be like a sand hour glass. On one the sensory input with loads of information, on the other side the output or the brain, and in the middle the channel capacity which restricts the flow of information.
This flow of information could widen/stretch by organizing the stimulus input simultaneously into several dimensions and successively into a sequence or chunks.
"N alternative stimuli, then his judgment enables us to narrow down the particular stimulus to one out of N/6."
Recoding
A person's memory could only contain a fixed number of chunks, however the amount of bits that are contained in each chunk could be increased.re
The author gives a good example of how the size of a chunk could vary through experience:
- some learning Morse code used one tone per individual chunk.
- soon groups of tones create letter taking up only one chunk.
- finally the tone sequence of a word take up only one chunk.
There are many ways to do this recoding, but probably the simplest is to group the input events, apply a new name to the group, and then remember the new name rather than the original input events.
Apparently the translation from one code to the other must be almost automatic or the subject will lose part of the next group while he is trying to remember the translation of the last group.
Interesting Quotes
"N alternative stimuli, then his judgment enables us to narrow down the particular stimulus to one out of N/6."
“When we have a large variance, we are very ignorant about what is going to happen. If we are very ignorant, then when we make the observation it gives us a lot of information. On the other hand, if the variance is very small, we know in advance how our observation must come out, so we get little information from making the observation”.
“It is interesting to consider that psychologists have been using seven-point rating scales for a long time, on the intuitive basis that trying to rate into finer categories does not really add much to the usefulness of the ratings”.
"Absolute judgment is limited by the amount of information. Immediate memory is limited by the number of items…the number of bits of information is constant for absolute judgment and the number of chunks of information is constant for immediate memory. The span of immediate memory seems to be almost independent of the number of bits per chunk"
Referance
The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information
