Memory Formative

8/3/2019 Memory Formative

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The Effect of Word Position, Word Frequency and Delay or Distraction after Encoding

on Free Recall.

Abstract

This experiment aimed to find out whether someone’s ability to freely recall words from a list

is affected by the position of the words in the list and by the words’ frequency in everyday

language. It also aimed to investigate the effect on short term memory of a delay and/or a

distraction task between initial encoding and recall. This was done using six word lists, split

into groups of high and low frequency words. Participants were required to watch the sets of

words being presented one by one on a computer screen, and then recall them in any order

under one of three conditions: either immediately, or after a 30 second delay during which

time they may be rehearsing the words they have seen, or after a 30 second delay with a

distraction task to prevent them from rehearsing. It was suggested that word frequency would

affect the primacy effect as high frequency words occurring at the beginning of the lists

would be recalled more accurately than low frequency words because they would already

have a strong presence in our long term memory. It was also predicted that the best recall

would be when there was no delay, and the worst recall would be in the condition where a

distracting task was used. It was found that both hypotheses were accurate. The results were

explained in terms of the primacy effect (we are more able to recall words at the beginning of

a list because they are rehearsed in the short term memory and gradually transferred into the

long term memory) and the recency effect (we remember words towards the end of a list

reasonably well too because our short term memory has received those pieces of information

most recently, so they haven’t yet decayed or been forgotten). Low frequency words were

only recalled accurately when they had been at the end of the list and the participant had

experienced the recency effect.

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Introduction

One of the first people to formulate a multistore model of memory was William James (1890,

cited in Loftus & Loftus, 1976). James’ theory was at first ignored due to the lack of

hypothesis and experimental support for the idea, but his notions were adopted by

Waugh and Norman (1965, cited in Baine, 1986) who developed their own concept

of a multistore model of memory. Their version suggested that we memory has two

components: primary memory (precursor to the short term memory as it is known

today, or STM, where we briefly hold memories of stimuli that we attend to) and

secondary memory (Today’s Long Term Memory, or LTM, where more permanent

memories are held). Waugh and Norman thought that if rehearsed, information in

the primary memory is more likely to enter the secondary memory.

Atkinson & Shiffrin (1968, as cited in Baine, 1986) formulated another multistore model of

memory, suggesting a store of ‘sensory memory’ before the STM. They suggested that the

sensory store had a large capacity and the ability to take a visual replica of the stimulus, but a

short time span of only up to 2 seconds. After this time the information is either lost or is

transferred to the STM if attended to. The STM is said to have a capacity of around only 7 (+

or - 2) items. Atkinson & Wickens (1971, as cited in Baine, 1986) suggested that as long as

rehearsal was maintained, the information would remain in the STM. Atkinson and Shiffrin

(1968, as cited in Baine, 1986) proposed that if the information was not rehearsed however, it

would decay in around 10 to 15 seconds. They believed that the STM is also used in the

recall of information, where memories from the LTM can become conscious short term

memories again and that memories in the LTM are said to be only lost via displacement. The

multistore model of memory is supported by neurophysiological evidence, such as that from

the case study of Clive Wearing, who suffered from anterograde amnesia after an illness and

was left without the ability to convert short term memories into long term memories. He was

unable to retain new memories for more than a few moments or fully access old ones. This

supports the multistore model because it suggests a distinction between long and short term

memories and also a link between the two stores. It is the operation of the STM in this model

that is most relevant to this study.

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One of the interesting phenomena that has been discovered through previous research into

behavioural evidence for the STM is the serial position effect, a term coined by Hermann

Ebbinghaus (Ebbinghaus, 1913). This refers to the finding that recall accuracy varies

depending on an item's position within a study list. When asked to recall a list of items in any

order (free recall), people tend to begin recall with the end of the list, recalling those items

best (the recency effect). Among earlier list items, the first few items are recalled more

frequently than the middle items (the primacy effect).

This study is based on an experiment originally conducted by Glanzer & Cunitz (1966a, as

cited in Herriot, 1974) who investigated the effect on the serial position curve of a delay

between the stimuli being presented and the time of recall. They found that with no

distraction, the primacy/recency curve looked as expected. With a ten second delay, the very

end of the curve did not rise quite as high as the curve with no delay, so recall was poorer.

With a 30 second delay however, recall was extremely poor. This demonstrates the limit of

the STM, suggesting it has a span of only 30 seconds at the most, and the importance of

rehearsal if for the stimuli to progress into the LTM. Perhaps the 30 second delay would only

have not had an effect if the stimuli were rehearsed in the STM for the entire 30 seconds, but

that would be difficult if the participant was being distracted, for example, so this experiment

uses a distraction task as one of the conditions before recall for comparison.

The experiment in this report is similar in design to that of Glanzer & Cunitz (1966a, as cited

in Herriot, 1974). The stimuli used were 6 word lists used in 6 conditions. Half of the word

lists contained high frequency words and the others contained low frequency words in order

to see if this affected our ability to remember the words. Within each of these 2 categories,

the time that elapsed between encoding and recall was altered each time. The options were 0

seconds, 30 seconds and 30 seconds plus a task. The task in the last condition was to distractthe participant in order to prevent them from rehearsing the list, to see if this would have

impact on the recency effect. It was predicted that similar results to those of their previous

experiment (Glanzer & Cunitz 1966a, as cited in Herriot, 1974) would be found, where the

longer the time elapsed and the addition of the task would mean that the participant’s ability

to recall words towards the end of the list would be severely reduced. The study’s further aim

was to see if low frequency words in the lists would be less well remembered than high

frequency words, as was suggested by Raymond (1969, as cited in Herriot, 1974). If this were

the case, it would be put down to our pre-existing familiarity with high frequency words and

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therefore link to our LTM. If the LTM was affected by the distraction task or the delay, we

would expect the primacy effect to change too, as our ability to rehearse and store those first

few words in the list would be reduced.

Thus, the first experimental hypothesis was that the lower the word frequency, the less we

expect a primacy effect, so the primacy effect would have a greater impact when high

frequency words were used. The second hypothesis was that during free recall, a normal

recency effect would be expected after no delay, with more words from the end of the list

being recalled accurately. It was predicted that there would be a reduced recency effect after a

30 second delay, and the worst recency effect and recall would be after a 30-second gap with

a distracting task to perform.

Method

Participants

The 58 participants used in the experiment were an opportunity sample of 18 to 35 year old

Psychology undergraduates. The mean age was 19.7 years. 29 were female and 29 were male.

It was not checked whether all the student’s native languages were English – if not, this

could have affected the results because it might be more difficult for them to remember a

word in a different language, as demonstrated in Craik and Tulving’s work on the semantic

level of processing (Craik and Tulving, 1975). If participants had reading difficulties such as

dyslexia this could also hinder their ability to remember the words when they were presented

in sequence. This was however, also not checked, but could be done in further research.

Apparatus

Two lists of 45 6-letter words were used, one consisting of high frequency words such as

‘colour’, ‘public’ and ‘decide’ and the other of low frequency words, such as ‘neuter’,

‘zealot’ and ‘lancet’. These words were then randomly assigned into six sets of fifteen words

that were shown to the participant on a screen. To do this, the participant accessed a

specifically designed computer programme, where they read on-screen instructions and then

viewed the word lists, and later typed in those which they could recall. The participants could

exit the screen which they were to type words into at any time by closing the window if they

didn’t remember any more. During the distraction task condition, the participant’s task was to

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count down from a certain number in given intervals, such as ‘count down in three’s, starting

from 99’ and they had to type their answers in whilst doing this to show they were doing it

properly. (See Appendix A for word lists, full instructions and examples of the data entry

screens).

Design

The experiment used a within-participants design and had two independent variables (IV): the

first was the word frequency, which had 2 levels, high and low. The other IV was

the delay / activities the participants partook in between seeing and recalling the

words. This was on three levels: (i) immediate recall, (ii) 30 seconds elapsed before

recall, allowing rehearsal and (iii) 30 seconds elapsed before recall, but with the

participant performing a simple counting task to prevent rehearsal. The dependent

variable (DV) was the number of words correctly recalled in each position on the

list. As previously mentioned, there were six conditions, which contained words

randomly selected from both high and low frequency lists and placed in the delay-

task conditions.

Procedure

Participants worked individually in separate booths with a computer and were presented with

on-screen instructions (see Appendix A). First there was a practice condition in which the

participant was able to get to grips with the task before then attempting all 6 other conditions,

where their results were recorded automatically.

The word lists were presented at a rate of 1 word per second and a maximum of 3 minutes

were allowed for recall. Recall was free, meaning the participants could recall the words inany order. The participants were aware that they would have to recall the words after the test

and so intentional learning was taking place. Participants were able to end the three minutes

prematurely if they could not recall any more words. For the task in the 30 seconds plus

distraction activity condition, participants were given a number and asked to take away a

figure from it until they could go no further or until the 30 seconds was up, whichever came

first.

Results

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Figure 1 shows that words in the middle of the list, from serial position 4-12 were particularly

poorly recalled, with the first and last words being apparently easier to remember. This

suggests a primacy and recency effect in the results, with the primacy effect having the

greatest impact when the word list contained high frequency words. This coincides with the

prediction that the primacy effect would be greatest when high frequency words were

recalled because the long term memory would be called into play. It is shown that the first

words in the series were better remembered than the last words in the series in the high

frequency word list, so the primacy effect was stronger than the recency effect. In the low

frequency word list, however, the opposite occurred - more words at the end of the list were

remembered than at the beginning of the list. For low frequency words, the recency effect

was greater than the primacy effect.

F igure 1: Average number of Correct Responses for the High and Low Frequency Word Conditions

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0

5

10

15

20

25

30

35

0 2 4 6 8 10 12 14 16

Serial Positio

A v e r a g e N o .

o f T i m e s C o r r e c t l y

R e c a l l e d

Low Frequenc

High Frequen



Figure 2 shows the curves of the graph when comparing the accuracy of recall in each of the

different conditions. This comparison is regardless of the difference in word frequency. The

difference between the three conditions is clear. With no delay, accuracy in recall was at its

highest, especially for the words later in the list. When 30 seconds elapsed and no task was

performed, the participant had time to rehearse those last few words, but recall was still less

accurate generally. In the condition where 30 seconds passed and the participant was given a

task to carry out, the recall accuracy in the recency period drops significantly. In the ‘0s’

condition, the last word in the list is correctly recalled 36 times. In the ‘30s + task’ condition,

this drops to just 17 times, less than half of the other. As expected, the delay at the end of the

task did not really have an affect on the primacy effect.

Figure 2: Average number of Correct Responses in Each of the Three conditions

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05

10

15

20

25

30

35

40

45

0 2 4 6 8 10 1 2 1 4 1 6

Se rial Po siti

A v e r a g e N o .

W o r d s R e c a l l e d

C o r r e c t l y 0s

30 s

30s + tas



the first test right through until the end, so found it harder to take in new words being shown

to them and push out the other words. Perhaps it would have been better to stretch the

experiment over a few days so that the last word list was not as fresh in the participant’s mind

as it would have been had they done each condition back to back, so any further research

should take this into account. Also, it has been suggested that the multistore model of

memory as proposed by Atkinson and Shiffrin is altogether too simplistic as it doesn’t

categorise different types of stimulus that might be encoded in different ways. For example,

Baddeley and Hitch (1974) elaborated the model to include a central executive, connected to

a phonological loop and a visual spatial sketchpad to show that there are different types of

stimulus that might be processed and remembered differently.

In order to ensure the interpretation of the results in this experiment is accurate, further

research should be carried out. Possible directions for this could include testing the delay

between encoding and recall in smaller increments of time, e.g. in 10 second gaps, in order to

get a more accurate span of the short term memory. Another possible alteration would be to

test using different lengths of word lists in order to see if this affects the primacy and recency

effects. It would be interesting to see if the very first and very last few words are the most

accurately recalled in a word list of any length.

References

Baine, D. (1986). Memory and instruction. Retrieved 21st January 2011 from

http://www.jstor.org/stable/4449528

Campbell, R., & Conway, M. A. (1995). Broken memories: Case studies in memory

impairment. Oxford, Blackwell.

Craik, F. I. M., & Tulving, E. (1975). Depth of Processing and the Retention of Words in

Episodic Memory. Journal of Experimental Psychology: 1975, Vol. 104, No. 3, p.268-

294

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Ebbinghaus, H. (1913). Memory: A contribution to experimental psychology. Columbia

University: Teachers College.

Herriot, P. (1974). Attributes of memory. Taylor and Francis.

Loftus, G. R., & Loftus, E. F. (1976). Human memory: The processing of information.

Routledge, Psychology Press.

Appendices

Appendix A – Data and Instructions for participants

See DUO.

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Memory Formative

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