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Cognitive Psychology PSY 504

Lesson 29

Memory

Atkinson & Shiffrin Model

This model is explaining the whole process of memory in short. How the information goes in

sensory register then in short term memory and in long term memory that is permanent store

information.

What do we study?

These all are the brief concepts in the study of long term memory.

Transfer from STM into LTM

Retrieval from LTM back into STM

Recall versus Recognition

Applications

Studying and testing

Role of rote learning

Eyewitness testimony

Long Term Memory

Cognitive psychology is about experiments. Psychologists do experiment to generate models,

and refine models.

Experiment

An important experiment was conducted by Anderson in 1976 to illustrate how speed of retrieval

varies with practice. In first phase they were given these sentences.

The Sailor is in the park.

The lawyer is in the church.

Subjects drilled over and over again until they know by heart.

Having these two sentences the subjects were tested on these sentences and asked whether

each was among the sentences they had studied.

The sailor is in the park.

The sailor is in the church.

Subjects knew the material enough to be correct almost all the time, experimenter was interested

only in the speed with which they made their correct recognition judgments.

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Cognitive Psychology PSY 504

Difference in study is because of the delay in presentation.

Results

The findings were:

Short Delay

Long Delay

Less Study

1.11

1.53

More Study

1.10

1.38

The time span of Less Study is .42 and More Study .28.

In less study and short delay condition subjects were fastest. And in more study condition with

short delay condition the rate was same. But in long delay condition and less study condition the

reaction time is 1.53.

Delay made difference. And more study also made difference.

The implication of this study was weaker memories take longer time to reactivate. If we want to

remember a thing we have to study it more.

Spread of Activation

Perlmutter & Anderson conducted an experiment that is unpublished, and cited in book of

Cognitive psychology.

In that experiment; subjects were presented with a sequence of words and asked togenerate

associates that began with specific letters. They had two conditions.

In priming condition there is pair of letters and words but these letters and words are associated.

Like Dog C for Cat, and bone- m for meat. In control condition the words and letters are

unrelated.

Control

Priming

Dog - C

Gambler C

Bone M

The reaction time of priming condition is 1.41 sec. and the reacton-time of

Control condition is1.53 sec.

Dog

Bone

Chase

part of

Cat

Eat

Meat

This network model is explaining the difference in both conditions. Through the word eat both dog

and bone is linked. There is relationship between these words. The results showed the priming

condition is easily recalled. Therefore the activating the network structure to answer the first

associate should help activate the structure needed to answer the second. This experiment

showed activation spreads through long term memory from active portions to other portions of the

memory and this spread takes time.

Associative Priming

Mayer & Schvaneveldt (1971) performed a classic demonstration of associative priming. They

had subjects judge whether or not pairs of items were words.

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Cognitive Psychology PSY 504

Positive Pairs Negative Pairs

Unrelated

Related

Non-word 1st

Non-word 2nd

Both non-words

Nurse

Bread

Plame

Wine

Plame

Butter

Wine

Plame

Reab

940

855

904

1087

884

If either item in a pair was a non-word, subjects were to respond no. where the top item was a

non-word, subjects were faster to reject the pair than when only the second item was a non-word.

Where the top item was not a word, subjects did not have to judge the second item and so could

respond sooner.

Subjects were fastest in the both non-words condition. Subjects were faster in the non-word first

condition than in the non-word second condition. In positive pairs subjects were much faster in

related pairs than in non-related pairs.

Implications

This result indicates that because subjects judged the first item to be a word, activation spread

from that word and primed information about the second, associatively related, item.

Judgment takes place in the working memory. The represenatation of the word has to be active in

short term memory.

We can read related material faster than non-related incoherent material where words might be

presented randomly.

The implication is that the associative spreading of activation through memory can facilitate the

rate at which words are read.

More Priming

Ratcliff & McKoon (1981) report a rather different priming demonstration of spreading activation.

They had subjects commit to memory sentences such as The doctor hated the book. Subjects

had to decide whether the noun "book" was in the studied sentence. Sometimes a prime word

such as "doctor" was presented just before "book".

Ratcliff & McKoon varied delay between Prime & Target from 50 to 300 ms. All of these intervals

were too short for subjects to develop any conscious expectations. The decrease in the reaction

time reflects the growth in the level of activation.

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Cognitive Psychology PSY 504

Implications

The implications of the experiment were

There is a strong effect of priming in the Long Term Memory that is strength of coding.

Activation spreads quickly up to 200 ms after which it slows down.

For recognition, information must first be activated and then inspected. Activation must spread to

info in LTM to be brought into STM. This takes time (200 ms).

We see the short term memory and long term memory are interacting. STM has less storage; at

one time it has 7 things. LTM keeps information all things. It has unlimited capacity for keeping

information. Another problem in STM is it has only 20 seconds duration of storage. But long term

memory has permanent storage.

For information to be used in a task as a recognition judgment, it must first be activated and then

inspected. When information is in long-term memory but not currently in working memory,

activation must spread to it, which takes some amount of time, as we saw in the McKoon and

Ratciliff study. Once activated, the time to inspect the information will depend on its level of

activation, as was illustrated in the Sternberg experiment.