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Cognitive Psychology PSY 504

Lesson 31

Memory

Interference

The fan effect is the name given to this increase in reaction time related to an increase in the

number of facts associated with a concept. It is so named because the increase in reaction time

is related to an increase in the fan of facts emanating from the network representation of the

concept. The term conveys the fact that additional information about a concept interferes with

memory for a particular piece of information. Interference affects a wider range of measures than

just recognition time. Fan effect is reserved for interference effects as measured by reaction time.

Historical Memories

Lewis & Anderson (1976) investigated whether he fan effect could be obtained with material the

subject knew before the experiment. They had subjects learned fantasy figures for example,

Napoleon Bonaparte was from India. Subjects studied 0-4 fantasy facts about each public figure.

After learning these facts they proceeded to a recognition-test phase. In this phase they saw

three types of sentences:

Fantasy world statements, true statements, and false statements like

1) Statements they had studied in the experiment

2) True facts about the public figurers (such as napoleon bonapartae was an emperor);

3) Statements about the public figure that was false both in the experimental fantasy world

and in the real world.

Subjects had to respond to the first two types of facts as true and to the last type as false.

Results

Subjects responded much faster to actual truths than to experimental truths. The advantage of

the actual truths can be explained, because these true facts would be much more strongly

encoded in memory than the fantasy facts because of greater prior exposure. The more fantasy

facts one learned about a person, the longer it took them to recognize something they already

knew about the person; Napoleon was an emperor.

Interference and Retention

Now we will consider what happens as these interfering effects get more extreme-either because

the to-be-recalled fact is very weak or because the interference is very strong.

There is evidence that the subject simply fails to remember the information under both conditions.

Results showing such failures of memory have traditionally been obtained with paired-associate

material, although similar results have been obtained with other material.

Experiment

In a typical interference experiment, two critical groups were defined.

The A-D experimental group learns two lists of paired associates,

The first list is List A-B: cat-43 and house-61

And second list is List A-D: cat-82 and house-37

The C-D control group also first studies the A-B list, but then studies a different second list,

List C-D is bone-82 and cup-37, which does not contain the same stimuli as the first list.

After learning their respective second lists, both groups are rested for their memory of their first

list, in both cases the A-B list.

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Cognitive Psychology PSY 504

Results

In general, the A-D group does not do as well as the C-D group with respect to both rate of

learning of the second list and retention of the original A-B list.

The results are presented in following figure.

Implications

The implication is that failure to recall is the extreme case of a long retrieval time. Thus, it is not

the case that the forgotten information is not in memory, but rather that it is in memory but is too

weak to be activated in the face of interference from other associations. Paired associate memory

is too weak to recall.

Forgetting is not actual loss of information but rather loss of ability to activate that information.

Recall versus Recognition

Consistent with the hypothesis that there exists in memory information that we can not recall is

the fact that we can recognize many things we cannot recall. This phenomenon suggests that

information can be in memory even though it cannot be activated in the recall test situation. The

memory network analysis makes clear the reason that recognition often works even when recall

fails. So, recognition is generally better than recall. For example if there is a question

Who invented the lenses we use in spectacles?

Then a huge fan of information networks becomes active. We recall a lot of information that is

related to glasses or spectacles.

For example someone mention Ibn-al Haitham invented the lenses we use in spectacles. If we

have listened this before now, then we can recall this answer because of strong enough

information. So, Joint activation helps the second statement.

There are many other possibilities. If with this question (Who invented the lenses we use in

spectacles? we have some options like, Michael, Ibne Batota, Albaroni and Ibn Al Haitham. Now

these options interfere with our information. And we become confuse. But because of our links or

network we can recall correct information. Like spectacles were invented by Muslim scientist so,

Michael could not be answer.

So, recognition is typically better than recall because a recognition test typically provides more

sources for activating memory. Recognition test is better than recall test. Tip of the tongue is

happened in recall not in recognition.

For example, if you see a man you say you have seen him before. So you can recognize him. But

you are not recalling his name.

In our daily life, in our exams, in any test or in other situation we think recognition is our friend and

recall is not much friendly.

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Cognitive Psychology PSY 504

Another example is if someone asks you when Baber came in Hindustan and invaded Hindustan.

The chances are we could not recall. If someone gives us some options like, 712, 789, 1566 and

1020 with question. Then it becomes easy to recognize when Baber invaded India.

So the conclusion of all that is recognition is a better and easiest task than recall.