An Experiment Into the Effect of Age on Serial Reproductive Memory

Psychology Coursework

An Experiment Into the Effect of Age on Serial Reproductive Memory

Abstract

Bartlett (1932) performed an experiment to investigate the reconstruction of memories. From this previous study the main aim of this investigation was to discover whether there is a correlation between age and its effect on serial reproductive memory. To conduct this research an experiment was devised where 2 groups of participants of 2 different ages were asked to listen to and reproduce the same story. There were the same numbers of people in each group, the members from both groups were chosen at random and all participants were chosen from a high school population. The results show that overall there was no difference between the groups in how much of the story was remembered.

Introduction

Serial Reproductive Memory is the name given to the type of memory that remembers events in sequence and then reproduces them whenever needed. This experiment aims to look at whether or not our Serial Reproductive Memory gets better or worse at remembering events as we get older.

Bartlett (1932) performed the ‘War of the Ghosts’ experiment. (The pioneering British social psychologist), Sir Frederic Bartlett asked readers of the story, 'The War of the Ghosts' (appendix 4), to try to rewrite it, recalling it as accurately as possible. They read it through twice and recalled it after delays varying from 15 minutes after study to several years later.

To most readers, this North American folk tale is fairly bizarre, and it is not surprising that in attempting to recall it, readers omit details, change things, and import new material.

Personal interests and experiences play a part in retelling stories from memory. But what is most interesting is that Bartlett's readers (typically unconsciously) made the story more orderly and coherent within their own cultural framework. His subjects were mostly well-educated English people at the time of the First World War, but subsequent experiments have shown similar tendencies amongst other groups. Typical transformations of the story are the following:

• 'Something black came from his mouth' tended to become 'he frothed at the mouth', 'he vomited' or 'breath escaped from his mouth'.

• 'Hunting seals' tended to become 'fishing'.

• 'Canoe' tended to become 'boat' and 'paddles' to become 'oars'.

• The wounded Indian tended to become the hero, whose wounds were sometimes even 'bathed' at the end.

• The reference by the Indian who stayed to the possibility of getting killed tended to be downplayed or dropped, whilst the reference to the probable anxiety of his relatives was usually given greater emphasis (the reference to having no arrows was often omitted).

•The role of 'the ghosts' (for some, they become a clan called the Ghosts; for others they were simply imagined by the Indian when wounded).

Hard to interpret items were omitted, including:

• Hiding behind the log;

• The connection between the Indian's injury and the termination of the battle.

Bransford and Franks (1971) carried out another similar experiment which demonstrated encoding distortion called Integration. This refers to the integration of numerous into one unified structure. When we are only able to remember the idea or the gist of events as opposed to a more detailed recollection this is due to integration.

The experiment involved the use of two sets of 30 sentences. People were required to read a sentence from the first set count to five and answer a question about the question. The purpose of the question was to ensure that comprehended the sentence correctly. This would be done with all 30 sentences. Below is an example of six of these sentences.

After a short time the second set would be shown and each person had tick a box indicating whether a sentence was old (in the previous set) or new.
From the results typically more than half the sentences were said to be old. The actual number of sentences that were repeated in the second set was zero. The results show that it is easy for ideas to become integrated.

The shadowing technique is a widely used experimental procedure, it requires an individual to listen to a series of words in one ear and then to try to repeat them back while having another series of words transmitted to the other ear.

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A study by Cherry (1953), showed that the individuals under the experiment noticed and remembered little about the second series of words, the unattended one, even when the language shifted from English to another language. But on the other hand, although, they did not seem to be aware of the semantic differences in the second series as much as they did in the first series; they were more aware of the physical differences in the second series, for example if the voices was becoming louder or deeper.

The shift in languages goes unnoticed as it is a semantic feature of the words dictated, semantic features are identified at a later stage of the processing however, a sensory feature such as pitch is identifiable at an early stage of the process.

In an experiment by Bower and Clark, 1969, two groups of individuals were given 10 words to remember. The first group was told to build a sentence or a story around the words given; the second group was not told anything about how to remember the words.

The experiment was repeated 12 times and it was found that the first group who attached some semantics to the words given could remember 94% of the words whereas the second group could only remember 14% of the words.

After reviewing this research it was decided to adapt Bartlett’s ‘War of the Ghosts’ experiment for this research. The idea was to reproduce the experiment and adapt it for two sub-groups. Another adaptation would be that instead of reading through the story and the writing it down the participant would be hearing a recording of the story and repeating it to another participant. In this research the aim is to discover whether there is a correlation between age and its effect on serial reproductive memory.

Hypothesis

The original story will differ more when reproduced by the group of younger children compared to the group of older children (directional).

Null Hypothesis

There will be no difference between the groups in how much the story differs, and any difference is due to chance factors.

Method

Design

The design of the research was an investigation using an independent groups design. This method research was chosen because the experiment is looking at two different variables. The results obtained from the experiment were then plotted in a table. The table had important points of the story, which were ticked if the participant remembered. Overall there were 32points to the story to be remembered. Variables that were controlled throughout the study were that the participants were students in either years 7 or 10 (depending on the group), the instructions for each participant was the same and the method with which the experiment was performed was the same for each participant. The minimum level of statistical significance considered for this investigation was 0.05 (5%).

Participants

Twenty-six participants from a target population of lower-school students were chosen to carry out this research. The first 13 participants were selected randomly from year 7 students; the second 13 participants were selected randomly from year 10 students.

Materials

For this research, one tape, with a recording of the original story (appendix 1); a microphone, to record the answers of the participants; and a tape recorder were used. The story used is an original Native American Sioux legend, which was chosen, as it is very unlikely that any of the participants had heard it before and also because it is from another culture. Standardised instructions were given to all participants (appendix 2).

Procedure

Two groups of randomly selected students were approached and asked if they would take part in the experiment. If willing the participants were then given a letter of consent to take home to their parents/guardian to sign and give informed consent, and asked to bring it back and hand in at a later date when the experiment would take place. On that date the first group of participants were then taken one at a time out of the classroom for the experiment. The first participant was taken into a separate room, had standardised instructions read out to them (appendix 2) and played a recording of the Native American Sioux legend ‘Unktomi and the Arrowheads’ and told to listen carefully. Then the next participant was brought into the room and the first participant repeated what they remembered of the story. The first participant was then taken into an isolated room next door and the third participant was brought into the experiment room. The second participant then told the third participant what they remembered of the story and were taken into the isolated room. This was repeated with all the participants in the group and then they were all briefed on what the experiment was about. The experiment was then repeated with the second group of participants and all the results put into a table (appendix 3).

Results

The results were plotted in a table (appendix 3), for every point in the story that was remembered the participant was given a point. The table shows the results of the data from each of the 26 participants. The results and the graph below show that more of the participants in group 1 (the older group) remembered more of the story, whereas the level of memory in group 2 (the younger group) dropped dramatically with the first three participants and then remained quite stable throughout the remainder of experiment.

From the graph above it would appear that the hypothesis has been proved and that serial reproductive memory is affected by age. However, to clearly discover whether or not this is the case the Mann-Whitney U Test was applied. This statistical test was chosen because the Mann-Whitney U Test is a recognised statistical test for comparing two different variables. The statistical workings can be seen in appendix 5.

Using the Mann-Whitney U Test produced a U value of 47 and a Critical Value of 45. As the U value is bigger than the Critical Value the hypothesis can be rejected and the null hypothesis is accepted. A significance level of 0.005 (5%) can be seen. There is therefore no significant difference between how much the story differs and age must not be a factor in how good our serial reproductive memory is.

Discussion

Results from this research show that the hypothesis could be rejected and that the null hypothesis could be accepted. This states that there is no significant evidence that age is a factor in how well our serial reproductive memory works. From the results of the Mann-Whitney U Test, it appeared that the aim of the research to discover whether age was a relevant factor in serial reproductive memory was achieved.

The data from the research shows that age is not a factor affecting serial reproductive memory. This means that both groups of participants should have scored more or less the same. However, the graph shows that the group with older participants scored higher points for longer whereas the group with younger participants were scoring lower points after fewer participants.

Another aspect of the changes in the story that was looked at was how much the stories changed and were westernised when reproduced by the two groups. These cultural changes were experienced much more frequently and dramatically than anticipated. Some examples of the changes from the older group are listed below:

• ‘Hit spider’ became ‘kill spider’

• ‘Unktomi’ became ‘obedywobedy’ which became ‘woobawooba land’ which then became ‘woopawoopa land’ which then became ‘whoopee cushion land’ which turned into ‘sat on a whoopee cushion’.

• ‘Hill’ became ‘street’

Also words or phrases which were not part of western culture became lost or forgotten for example:

• Passing the peace pipe

• Chief of the tribe

The younger group also westernised the legend, perhaps even more so, for example: Cowboys, Indians and Doctors all appeared, which are all western ideas.

This clearly shows that people are very ethnocentric and tend to look at things from their own cultures point of view.

This research could be useful in taking into account that not all eyewitness testimonies may be true. The fact that serial reproductive memory fades over time, as Bartlett found in 1932, and also the fact that people tend to look at things and change events so it fits in with their society would need to be taken into account.

However the research is limited in that only a comparatively small number of participants were tested and also the graph showing the total number of points remembered by each participant in each group contradicts the findings of the Mann-Whitney U Test. Also this only shows the affect of serial reproductive memory in one society. Another limitation is that the age groups are relatively close together, only three years apart.

To improve the research more participants would need to be tested, the experiment would need to be repeated in other cultures in other parts of the world and also the age range between groups needs to be a lot bigger. In addition the experiment could also be repeated with more than two age groups, testing four or five different age groups to find if there is an age where serial reproductive memory works best.

Bibliography

http://www.worc.ac.uk/departs/psycho/UG_Courses/Archive/2001-2002/Psy280/Lecture6.html

Bartlett, F.C.; Remembering. Cambridge: Cambridge University Press; (1967 [1932])

Coolican, H; Research Methods and Statistics in Psychology; Hodder and Stoughton; 1999

Gross, R; Psychology the Science of Mind and Behaviour (4th Edition); Hodder and Stoughton; 2001

Gross, R, McIlveen, R, Coolican, H, Clamp, A, Russell, J; Psychology a New Introduction for A Level; Hodder and Stoughton; 2000

http://www.psybox.com/web_dictionary/Bartlett.html

http://www.psychology.psych.ndsu.nodak.edu/malone/Psych461/War%20of%20the%20Ghosts.Ch1.htm

Appendix

1. UNKTOMI AND THE ARROWHEADS

Sioux

Native American Lore

There were once upon a time two young men who were very great friends, and were constantly together. One was a very thoughtful young man, the other very impulsive, who never stopped to think before he committed an act.

They ascended a high hill, and on reaching the top, heard a ticking noise as if small stones or pebbles were being struck together.

Looking around they discovered a large spider sitting in the midst of a great many flint arrowheads. The spider was busily engaged making the flint rocks into arrowheads. They looked at the spider, but he never moved, but continued hammering away on a piece of flint which he had nearly completed into another arrowhead.

"Let's hit him," said the thoughtless one. "No," said the other, "he is not harming any one; in fact, he is doing a great good, as he is making the flint arrowheads which we use to point our arrows."

"Oh, you are afraid," said the first young man. "He can't harm you. Just watch me hit him." So saying, he picked up an arrowhead and throwing it at "Unktomi," hit him on the side. As Unktomi rolled over on his side, got up and stood looking at them, the young man laughed and said:

"Well, let us be going, as your grandfather, "Unktomi," doesn't seem to like our company." They started down the hill, when suddenly the one who had hit Unktomi took a severe fit of coughing. He coughed and coughed, and finally small particles of blood came from his mouth. The blood kept coming thicker and in great gushes. Finally it came so thick and fast that the man could not get his breath and fell upon the ground dead.

The thoughtful young man, seeing that his friend was no more, hurried to the village and reported what had happened. The relatives and friends hurried to the hill, and sure enough, there lay the thoughtless young man still and cold in death. They held a council and sent for the chief of the Unktomi tribe. When he heard what had happened, he told the council that he could do nothing to his Unktomi, as it had only defended itself.

Said he: "My friends, seeing that your tribe was running short of arrowheads, I set a great many of my tribe to work making flint arrowheads for you. When my men are thus engaged they do not wish to be disturbed, and your young man not only disturbed my man, but grossly insulted him by striking him with one of the arrowheads which he had worked so hard to make. My man could not sit and take this insult, so as the young man walked away the Unktomi shot him with a very tiny arrowhead.

This produced a haemorrhage, which caused his death. So now, my friends, if you will fill and pass the peace pipe, we will part good friends and my tribe shall always furnish you with plenty of flint arrowheads." So saying, Unktomi Tanka finished his peace smoke and returned to his tribe.

Ever after that, when the Indians heard a ticking in the grass, they would go out of their way to get around the sound, saying, Unktomi is making arrowheads; we must not disturb him.

Thus it was that Unktomi Tanka (Big Spider) had the respect of this tribe, and was never after disturbed in his work of making arrowheads.

2. Standardised Instructions

3. Table of Results

4. War of the Ghosts

One night two young men from Egulac went down to the river to hunt seals, and while they were there it became foggy and calm. Then they heard war cries, and they thought: "Maybe this is a war party." They escaped to the shore, and hid behind a log. Now canoes came up, and they heard the noise of paddles, and saw one canoe coming up to them. There were five men in the canoe, and they said:

"What do you think? We wish to take you along. We are going up the river to make war on the people."

One of the young men said: "I have no arrows."

"Arrows are in the canoe," they said.

"I will not go along. I might be killed. My relatives do not know where I have gone. But you," he said, turning to the other, "may go with them."

So one of the young men went, but the other returned home. And the warriors went on up the river to a town on the other side of Kalama. The people came down to the water, and they began to fight, and many were killed. But presently the young man heard one of the warriors say: "Quick, let us go home: that Indian has been hit." Now he thought: "Oh, they are ghosts." He did not feel sick, but they said he had been shot.

So the canoes went back to Egulac, and the young man went ashore to his house, and made a fire. And he told everybody and said: "Behold I accompanied the ghosts, and we went to fight. Many of our fellows were killed, and many of those who attacked us were killed. They said I was hit, and I did not feel sick."

He told it all, and then he became quiet. When the sun rose he fell down. Something black came out of his mouth. His face became contorted. The people jumped up and cried.

He was dead.

5. Mann-Whitney U Test