Memory:Activation in a network, Magic number 7, Chunking

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Cognitive Psychology PSY 504

Lesson 25

Memory

Short Term Working Memory

Short term memory and Working Memory are same. Some psychologists distinguish short term

memory and working memory but majority of Psychologist Do not. Another important thing in

memory is Attention. Attention plays an important and critical role in short term memory. Duration

of short term memory is about 20 seconds. Working Memory is a memory that we use to function.

Not the same thing as remembering what happened yesterday as opposed to a long time ago.

The conscious is short term memory. Long Term Memory is an infinite storehouse. After 20

seconds what we can remember is long term memory. So, short Term Memory is limited in

capacity.

Working Memory: an activation model

John Anderson worked a lot on parallel process. He presented this activation model and said

working memory sees short term and Long term memory as qualitatively different. But some

other psychologists see LTM and STM similar but with some differences. There are certain

differences. According to activation model working memory has something which has a certain

level of activation (above threshold). Outside information is also involved in this activation model.

The items in working memory are defined by a high level of activation, which enables reliable and

rapid access to them. Attention is a part and parcel of this activation mechanism off short term

working memory. Attention relies on rehearsal. There is limitation in Short term memory

rehearsal. If unattended the items in working memory will rapidly decay away in their level of

activation. One can maintain items in working memory by rehearsing them and keeping them in a

highly active state. There are limitations on how many items one can rehearse before they decay.

Activation in a network

This is a network of words. We can say this is a semantic network. Different words with links are

presented. Like at bottom there is a word penguin. This word has two direct links swimming and

bird. These two words have other links like shark, flying, animals, fish, and sparrow. This is a

network of long term memory. These networks help in the activation of short term memory.

For example, if there are some concepts related to penguin like sea, atmosphere then we can

recognize this penguin.

If we are seen desert we can remember camels. Because we are used to see camel in desert.

So, these all information is saved in our long term memory, with clues we can remember things

like camel in desert. So the effect of context is also very important even in working memory

because it active other related nodes.

Cognitive Psychology PSY 504

Magic number 7

John Miller was a great cognitive psychologist. He presented model of memory.

He wrote in an article,

"My problem is that I have been persecuted by an integer. For seven years this number has

followed me around, has intruded in my most private data, and has assaulted me from the

pages of our most public journals. This number assumes a variety of disguises, being

sometimes a little larger and sometimes a little smaller than usual, but never changing so

much as to be unrecognizable. The persistence with which this number plagues me is far

more than a random accident. There is, to quote a famous senator, a design behind it, some

pattern governing its appearances. Either there really is something unusual about the number

or else I am suffering from delusions of persecution."

This number is 7. He said it is very important. It is limit of items how many items we can keep in

our memory. Plus minus 2 is range of 7.some people can remember 5 numbers and some can

remember 9 numbers. It means 7-2=5, 7+2=9.

We can understand this by an example. We give a list of 7 digits to our friends for remembering. It

is normal if people can recall 5 and 7 digits. But if people can recall less than 5 then there is some

problem with these people. Some people have good memory they can recall 9 digits.

If we look in our religion we have seven days in our week. There are seven seas, seven

continents, and seven skies. So 7 is our limit of our short term memory.

A question arises here, that is people can learn more than 7 words, 7 letters, seven sentences.

These seven letters LJKWNPR are easy to learn. But if this list of cities,

London, Paris, Munich, Berlin, Madrid, Prague, Stockholm, is given to people. People can learn it.

So, how interesting people can learn these 40 digits? So, magic number & is not physical unit it is

semantic unit or meaningful unit.

An example of all this can be, you are in a market and watching shirts, you like 30 shirts but you

can remember only 7 or 8 shirts in short term memory at a same time. Some people collect

samples and then select the best possible from these samples.

In decision-making, need for awareness of limitations of Short Term Memory. Our long term

memory has a long storage capacity but our short term memory is limited. That's why people

need to keep diaries. They note all important things in these diaries. Because our short term

memory does not have capacity.

Chunking

There is another way of remembering things that is chunking.

For example a telephone Number in USA is 6174927861. this number has more than 9 digits. It is

not easy to recall it. So the easy way to remember this number is chunking. Like

617-492-7861

In Pakistan people make chunks in different way than USA like,

617-49-27-861

But some time problem can arise when we tell phone numbers to a person who has different way

of making chunks. Like some recall three by three digits, some recall digits two by two. So other

can face problem in remembering others chunks.

Chunking is a way to increase capacity. Capacity of STM varies with meaningfulness of the

material. A chunk is a memory unit. STM capacity is not limited by a physically defined unit but by

a meaningfulness unit. Through chunking we can learn 21 digits at a time. Words limit is seven.

But the capacity of sentence is much lower than letters and words.

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