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Serial position effect

Psychology HL

11/18/2016

Meghna Burad and Candidate No.

No. of words -

Table of Contents

Title Page……………………………………………………………………………………………………………………………… Abstract………………………………………………………………………………………………………………………………… Introduction……………………………………………………………………………………………………………………….. Method………………………………………………………………………………………………………………………………. Results………………………………………………………………………………………………………………………………… Discussion……………………………………………………………………………………………………………….. References………………………………………………………………………………………………………………. Appendix i Standardized directions…………………………………………………………………………………. Appendix ii Informed consent letter……………………………………………………………………………… Appendix iii Informed parental consent letter…………………………………………………………………. Appendix iv Debriefing Notes…………………………………………………………………………………….. Appendix v List of words for the participant groups………………………………………………………. Appendix vi Raw Data…………………………………………………………………………………………………. Appendix vii Mann Whitney Calculations……………………………………………………………………….

Abstract

The Serial position effect, a cognitive bias, refers to the tendency of the human brain to recall the items present in the beginning/ending of the list with a higher probability when compared to the middle of the list, suggesting that position affects the frequency of recall. A loose replication of Glanzer and Cunitz (1966) was conducted and it was aimed to investigate how the position of the words affected recall and the alteration of the variables ‘Rate’ and ‘Interval’

The Serial position effect is the tendency of the human brain to recall the items present in the beginning and the ending of the list the best and it is a cognitive bias. The Primacy and the Recency effect suggests that if a list of words is read out or shown to a person, she/he is more likely to remember the first/last words present in the list. We carried out the replication and modification of the experiment conducted by Glanzer and Cunitz in 1966 which aimed to test whether participants would remember the first 8 words and the last 8 words more than the middle 8 words in the list of 24 words. Two control and experimental groups were used, the first control and experimental group was shown the words using a presentation on the computer screen and the second control and experimental group was read out the words through speech. This further helped us compare the results as it allowed us to analyse whether participants remembered more words by viewing it or by listening to it. However, it was hypothesized that both the primacy and the Recency effect would be shown in the results of participants of both groups. The independent variable was the positioning of the 24 words. The dependent variable was the number and position of the words remembered by each participant. The null hypothesis was rejected on the basis of the descriptive and the inferential data. It can be concluded that the results were statistically significant and therefore the null hypothesis is rejected thus more words shall be retained when the group of words is the first one-third and last one-third of the list when opposed to the second one-third of the list.

Word count: 287

Introduction

The serial position effect, a cognitive bias, refers to the tendency of the human brain of recalling the items present in the beginning and the ending in a list better than the middle ones. It is regarded as evidence for Atkinson and Shiffrin’s multi-store model explaining that the items in the beginning of the list are retained in the long-term memory store, owing to the primacy effect, and the items in the ending of the list are retained in the short-term memory store, owing to the recency effect.

A study conducted by Peterson and Peterson (1959) aimed to determine the duration of short-term memory in order to present experimental proof for the multi-store model and distinguishing between the duration of the long-term and short-term store. Participants were asked to recall trigrams after different intervals. To evade rehearsal, the Brown-Peterson technique was used on participants. Results showed that the longer the interval, the lesser trigrams were recalled supporting the multi-store model as it states that the short-term memory store has a limited duration when rehearsal is prevented.

The multi-store model of memory by Atkinson and Shiffrin describes a distinction between three memory stores; sensory, short-term and long-term memory stores. The sensory memory store is responsible for the iconic and echoic memory. The sensory memory store stores information retained long enough by our senses to be utilized, supported by studies Peterson and Peterson (1959) and Miller (1956) regarding the duration and the amount of information the can be stored. The model stated that information stored in the Short-term memory store could be transferred to the Long-term memory store if it is repeated.

I partially replicated the experiment by Glanzer and Cunitz (1966) which aimed to determine whether the serial position curve consisted of two curves representing the output from distinct short-term and long-term storage mechanism. It attempted to prove this by altering variables such as presentation rate, interval and repetition that affected one storage mechanism and had no effect on the other. The original study found out that the rate at which the words were presented and the interval between the words presented and the recalling of the terms, affected the short-term memory, therefore affecting the recency effect or the end of the curve produced. Furthermore, repetition of the words presented affected the long-term memory, therefore affecting the primacy effect or the beginning of the curve produced.

Aim: To investigate how the variables altered, affect the Primacy and Recency effect and how the position of the words affects recall

Null Hypothesis: The curve produced will not represent two different curves or distinct storage mechanisms. The variables altered would not affect the recency effect and would rather affect the primacy effect.

Research Hypothesis: The bimodal serial position curve produced from the results will represent the distinct short-term and long-term storage mechanism. The variables ‘rate at which the words are presented’ and the ‘interval between presentation of words to recall’ affect the recency effect curve and will not have an effect on the primacy effect curve.

It is hypothesized that an Increase in the variable ‘rate’ would display an increase in the mean for the recency section of the list and would not affect the mean for the primacy section of the list. An increase in the variable ‘Interval’ would decrease the mean for the recency section and not affect the mean for the primacy section.

Method

Design

The research method for my IA is experimental. The design used is independent measures. The type of data collected will be nominal and will be presented in the form of descriptive and inferential data.

A list of 20 words was prepared. During the preparation of the list, it was ensured that words with obvious connections and recognitions weren’t inputted in this list. For example the word ‘Watch’. The word ‘Watch’ would have had an obvious connection as a Watch was part of the equipment used, in order to time the participants. Each word present in the list consisted of 5 letters. This was done to ensure that the words shown or recited to the participants were not very difficult to be recalled by the participants. The words used were simplistic words rather than complex words further diminishing confounding variables affecting results.

All the participants viewed the words on a Laptop screen in the same order. The variables altered were the rate at which the words were presented, which refers to for how long each word was shown, and the interval, which refers to the time a participant views a blank screen before producing the recollected words on a paper by writing. This allowed the recognition of correlations between the variables and the data produced. The controls were the no. of words the participants were presented with, and the repetition of each word, which refers to the number of times each word was presented to each participant. The time provided to each participant for the producing of the words recollected in written was controlled and was 2 minutes.

|||The procedure was not repeated with each participant as this would result in additional factors hindering the collection of appropriate results in the experiment. It would lead to confounding variables for instance the participants would attempt to improve the amount of words memorized with respect to the first trial; they might remember the words from the first trial, altering the results achieved; or they might pay less attention to the words as they have already been exposed to that word list before.

The independent variable was the position of the words in the list of 20 words. The first part of the list consisting of 7 words is referred to the Primacy effect and the last 7 words refer to the Recency effect. The intermediate group comprises of 6 words.

The dependent variable refers to the frequency of the words remembered from the Primacy section of the list and the Recency section of the list.

As the factors being altered are hypothesized to affect the Short-term memory store and not affect the Long-term memory store, the frequency of the words remembered from the Recency section should remain the same in every condition and not be affected by the alteration of variables.

Informed consent and Informed parental consent was given by participants to ensure that ethical considerations were made during the conduct of the experiment. Debriefing was conducted by providing an explanation of the aim of the study and the results, right after the experiment was conducted and right after data analysis was completed. Other ethical consideration such as protection from harm, confidentiality and right to withdraw was also followed.

Participants

24 participants were derived from opportunity sampling as it was easier, faster and more efficient to employ participants using opportunity sampling. The target population was of 15-18 year old multicultural high school students belonging to collectivistic cultures. The students were randomly separated into two groups one in which the variable Rate was kept as control as the variable Interval’s effect was investigated, and in the other group the variable Interval was kept as control as the variable Rate’s effect was investigated. Each group consisted of 12 participants. All participants were fluent in English and consisted of 19 females and 5 males.

The limitation in the participant sample was that the participants were not representative of the whole population as they were students who belonged to a specific age range, belonged to collectivistic cultures and the sample size was small consisting of 24 participants.

Materials

Standardized instructions for participants (appendix i)

Informed letter of consent (appendix ii)

Informed letter of parental consent (appendix iii)

Debriefing notes (appendix iv)

Wordlist of 20 words for participants (appendix v)

Paper and pen for the producing of the recollected words

Stopwatch to time the participants

Quiet and well-lit room (consisting of no objects and disturbances that might result in being distractions)

Tabulated record sheet to record results for analysis and discussion.

Procedure

All participants were provided with standardized directions (appendix i) and an informed letter of consent (appendix ii) that they were asked to sign to be able to take part in the experiment. Participants under the age of 18 were provided with informed letter of parental consent (appendix iii) and were asked to get it signed from their parents to show approval of their child’s involvement in the experiment. The participants were then asked how old they were and if they were fluent in English.

Both the groups were shown a list of 20 words on a laptop screen using a presentation. Two groups were presented with different conditions. The variable Rate was kept constant for the first group and the variable Interval was altered. The Rate was kept as 1S, where a single S consisted of 3 seconds. The Intervals were kept at 0, 15 and 30 seconds, where 4 participants were given the same condition. The variable Interval was kept constant for the second group and the variable Rate was altered. The Interval was kept as 15 second. The Rates were kept at 1S (3seconds), 2S (6seconds) and 3S (9seconds), where 4 participants were given the same condition. During the Interval, the participants were shown a timed white blank screen. As the screen turned black, the participants were given with 2 minutes to write down as many words as they could recollect on a piece of paper.

The participants were then informed of the experiment’s aim and after the data analysis was conducted, the participants were informed of the findings and the implications of the findings of the experiment.

Results

E. Results: Descriptive data

The Independent measures design was used and ordinal data was acquired.

The mean, serving as the measure of central tendency, derived from the raw data for each condition and each section of the word list represented the probability a word from that section of the word list would be recalled. The graphs for the mean visually displayed the differences in the mean for each section of the word list, exposed to different conditions. This data reflected the first part of the aim, determining the effect the alteration of the variables had on the probability of word recall from each section of the list.

For the group with S as control and Interval as experimental, it was hypothesized that the primacy mean would be the same for each condition. For Intervals 0, 15 and 30, the mean values were 0.68, 0.68 and 0.61 representing minimal difference of 10-11% of the value, supporting the hypothesis. It was hypothesized, that as the intervals increase, the recency mean would decrease. The mean for interval 0 was 0.54, 15 was 0.68 and 30 was 0.46. This was shown true for the conditions 0 to 30 or 15 to 30, however, was proved false for 0 to 15 as the mean showed an increase, disproving the hypothesis.

For the group with Interval as control and S as experimental, it was hypothesized that the primacy mean would be the same for each condition. For rate 1S, 2S and 3S, the mean values were 0.71, 0.86 and 0.79. The differences in these mean values were quite significant as the differences ranged from 9-21% of the original values, disproving the hypothesis. It was hypothesized, that as the rate increases, the recency mean would increase. The mean for 1S was 0.39, 2S was 0.25 and 3S was

0.57. This was true for 1S to 3S and 2S to 3S, however was false for 1S to 2S, disproving the hypothesis, similar to the first group’s results.

The U-curve graphs reflected the second part of the aim determining how the position of the words affected recall by displaying the frequency of the words with respect to their position on the word list. The U-curved graphs proved the research hypothesis as the U-curve graph represented the bimodal serial position curve as it represented two different curves representing two distinct storage mechanisms.

Inferential data

The independent measures design was used and the ordinal level of measurement was used. The Mann Whitney U-test was used. Because of the size of the sample and the lack of a standard distribution of data, the level of data was reduced to ordinal, and therefore the U-test was used. The Mann-Whitney U-test computes the level significance for the independent measures design and represents the data of a small sample with the greatest accuracy, providing a relationship between the IV and DV, and allowing us to reject or accept the null hypothesis.

The Mann-Whitney U-test was performed twice on the raw data. The values used were of the 0.05 directional test values.

The first time it was conducted was to determine whether the alteration of the variables had an effect on the Primacy effect or not. The results showed that the UA value of 100 was larger than the 0.05 lower limit value of 42, and the UB value of 44 was smaller than the 0.05 upper limit value of 102, causing us to accept the null hypothesis. The P values were of 0.0559 and 0.1118, being greater than the limit of 0.05, further causing us to accept the null hypothesis.

The second time it was conducted to determine whether the alteration of the variables had an effect on the Recency effect or not. The results showed that the UA value of 44 which was greater than the 0.05 lower limit value of 42, and the UB value of 99.5 which was smaller than the 0.05 value of 102, causing us to accept the null hypothesis. The P values amounted to 0.0594 and 0.1188 which were greater than the limit value of 0.05, further causing us to accept the null hypothesis.

In both the tests, the research hypothesis was rejected, with respect to the inferential data. The U values do not match the critical values of significance, and thus, the results may be due to chance and confounding variables. The confounding variables would include effectiveness of memory, memorization techniques, fluency in the English language, focus during the conduct of the experiment and previous state of mind. The choice of words also affected what the participants remembered, as the familiarity with each word for different participants is different for all people. These confounding variables affected the results of the experiment. The participant sample was very small to derive a definite causation.

However, a causation can be seen from the descriptive data. Had the variables been more controlled, the participant sample larger, a definite cause and effect relationship could have been derived.

Discussion

With reference to the statistics, part of the research hypothesis has been rejected referring to the alteration of variables affecting the Primacy and Recency effect. However, the part of the research hypothesis referring to the presence of two curves representing two distinct storage mechanisms as in the bimodal serial position curve, proven.

The results derived from the original Glanzer and Cunitz (1966) experiment differs from the findings of this experiment.

Works cited

Appendix i Standardized directions

Standardized directions for all participants:

1. Before you begin the experiment, ensure that you are calm.2. Be ensured that this is not a memory test, so do not be stressed about how much you can

remember. 3. Read the 20 words presented on the laptop screen, placed in front of you.4. Begin writing down the words you remember on the empty sheet of paper given as soon as

you see a dark screen saying ‘end of slideshow’. 5. Write down as many words as you can remember within a two minute time frame.

Appendix ii Informed consent letter

Dear participant,

I am a student from Wells International School and am replicating and modifying a previous psychology experiment for an internal assessment for my IB Psychology HL class. The purpose of this study is to investigate the Primacy and Recency effect in free recall. If you wish to participate in this experiment you should know that during this experiment:

No psychological or physical harm would be caused. All data collected will be kept confidential. Taking part is voluntary.

If you have any further questions you can contact me using this number: ########.

You will be given a copy of this form to keep for your records

Statement of Consent: I have read the above information, and have received answers to any questions I asked. I provide consent for myself to take part in the study.

(Please tick box for agreement)

Participant’s Full name ______________________________

Participant’s Signature ___________________

Date _________________

Appendix iii Informed parental consent letter (for participants under the age of 18)

Dear parent/guardian,

I am a student from Wells International School and am replicating and modifying a previous psychology experiment for an internal assessment for my IB Psychology HL class. The purpose of this study is to investigate the Primacy and Recency effect in free recall. If you allow your child to participate in this experiment you should know that during this experiment:

No psychological or physical harm will be caused. All data collected will be kept confidential. Taking part is voluntary.

If you have any further questions you can contact me using this number: #########

You will be given a copy of this form to keep for your records.

Statement of Consent: I have read the above information, and have received answers to any questions I asked. I provide consent for my child to take part in the study.

(Please tick box for agreement)

Parent/Guardian Full name _________________________________________________

Parent/Guardian Signature _________________________________________________

Participant’s Signature ___________________________________

Participant’s Full Name ___________________________________

Date ________________________

Appendix iv Debriefing notes

Dear participants,

We would like to thank you for participating in our study. This experiment was based on the Primacy and Recency effect theory, which suggests that when people try to recall a list of words they have tried to memorize, the first and the last words in the list have a higher chance of being recalled.

The Primacy effect occurs due to the words from the beginning of the list being remembered as they are hypothesized to be stored in the long-term memory store, The Recency effect occurs due to the words from the ending of the list being remembered as they are hypothesized to be stored in the short-term memory store.

All the participants were divided into two groups. The participants in the first group were investigated for the effect of Interval on the Primacy effect. The participants in the second group were investigated for the effect of Rate on the primacy effect. The rate refers to the rate at which words were presented and the interval refers to the time between the end of the presentation of words and the time during which participants record the words they can recall.

We looked at the results from both groups, and found out that both of the groups were able to remember more of the first and last words from the list.

Our findings are supported by the fact that we found that our independent variable, the words and their position on the list, had an effect on the dependent variable, which was the number of words you recall and their positions.

These results are consistent with the study that we were replicating, which was done by Glanzer and Cunitz in 1966. We would like to remind you that your data shall remain confidential, and your participation in our study is greatly appreciated.

Appendix v List of words for the participant groups

The word list was the same for all groups which further allowed us to eliminate confounding variables.

1. Baker2. Quick3. Joker4. Zebra5. Climb6. Amaze7. Click8. Brace9. Crash10. Slide11. Catch12. Broad13. Mixed14. Cream15. Weigh16. Peach17. Night18. Crane19. Shape20. Juicy

Appendix vi Raw data

S as control, Interval as experimental

Participan nRate Interval age words remembered position wise

tP1 1S 0 17 1,2,3,14,18P2 1S 0 18 1,3,4,5,10,15,17,18,19,20P3 1S 0 17 1,2,3,4,5,6,10,12,13,15,17,18,20P4 1S 0 18 1,2,3,5,6,7,10,12,14,17,18,19

P5 1S 15 181,2,3,4,5,7,8,9,10,11,12,13,14,16,17,18,19,20

P6 1S 15 17 1,2,3,4,5,6,7,10,11,12,13,14,16,19,20P7 1S 15 17 1,3,4,13,14,17,18,20P8 1S 15 17 1,2,3,14,15,16,17,18,20P9 1S 30 17 1,2,3,4,7,11,13,14,15,16,17,20P10 1S 30 17 1,4,6,7,18,20P11 1S 30 17 1,2,3,4,9,11,14,16,17,19P12 1S 30 17 1,2,5,7,9,10,14,16,20

Interval as control, S as experimental

Participant nRate Interval age words remembered position wiseP13 1S 15 17 1,2,5,10,11,12,13,14,15,16,17,19,20P14 1S 15 17 1,2,3,4,5,6,7,8,10P15 1S 15 17 1,2,3,4,5,8,16,18,20P16 1S 15 17 1,2,4,5,6,14,20P17 2S 15 17 1,3,4,5,6,7,8,9,11,14,16,20P18 2S 15 15 2,3,4,5,6,8,9,12,13,16,20P19 2S 15 17 1,2,3,4,5,6,7,13,14P20 2S 15 17 1,2,3,4,6,7,10,12,13,16P21 3S 15 15 1,2,3,4,5,6,8,14,16,20P22 3S 15 16 1,2,3,4,7,11,12,14,15,16,17,20P23 3S 15 16 1,2,3,4,5,6,10,11,12,13,15,16,17,18,20P24 3S 15 15 1,2,3,5,6,10,11,13,17,18,20

S as control, Interval as experimental (words remembered by individual participants)

1S and 01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

4 3 4 2 3 2 1 0 0 3 0 2 1 2 2 0 3 4 2 2

1S and 151 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

4 3 4 3 2 1 2 1 1 2 2 2 3 4 1 3 3 3 2 3

1S and 301 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

4 3 2 3 1 1 3 0 2 1 2 0 1 3 1 3 2 1 1 2

Interval as control and S as experimental

15 and 1S1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

4 4 2 3 4 2 1 2 0 2 1 1 1 2 1 2 1 1 1 3

15 and 2S1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

3 3 4 4 3 4 3 2 2 1 1 2 3 2 0 3 0 0 0 2

15 and 3S1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

4 4 4 3 3 3 1 1 0 2 3 2 2 2 2 3 3 2 0 4

S as control, Interval as experimental – total for each participant

1S and 0 Primacy total Recency totalP1 3 2P2 4 5

P3 6 4P4 6 4

1S and 15 Primacy total Recency totalP1 6 5P2 7 4P3 3 4P4 3 6

1S and 30 Primacy total Recency totalP1 5 5P2 4 1P3 4 4P4 4 3

Interval as control, S as experimental – total for each participant

15 and 1S Primacy total Recency totalP1 3 6P2 7 0P3 5 3P4 5 2

15 and 2S Primacy total Recency totalP1 6 3P2 5 2P3 7 1P4 6 1

15 and 3S Primacy total Recency totalP1 6 3P2 5 5P3 6 5P4 5 3

Appendix vii Serial position curves

S as control, Interval as experimental (serial position curves)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 200

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Interval 0 Interval 15 Interval 30

position

frequency

Interval as control, S as experimental (serial position curve)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 200

0.5

1

1.5

2

2.5

3

3.5

4

4.5

1S 2S 3S

position

frequency

Appendix viii Processed data

S as control, Interval as experimental (total words remembered by participants)

1S and 0primacy total middle total recency total

19 6 15

1S and 15

primacy total middle total recency total19 11 19

1S and 30primacy total middle total recency total

17 6 13

Interval as control, S as experimental (total words remembered by participants)

Interval as control S as experimental15 and 1Sprimacy total middle total recency total

20 7 11

15 and 2Sprimacy total middle total recency total

24 11 7

15 and 3Sprimacy total middle total recency total

22 10 16

S as control, Interval as experimental (mean for each section)

1S and 0

primacy mean middle meanrecency mean

0.68 0.25 0.54

1S and 15

primacy mean middle meanrecency mean

0.68 0.46 0.68

1S and 30

primacy mean middle meanrecency mean

0.61 0.25 0.46

1S and 0 1S and 15 1S and 302.25

2.32.35

2.42.45

2.52.55

2.62.65

2.72.75

Primacy mean - S as control, In-terval as experimental

1S and 0 1S and 15 1S and 300

0.5

1

1.5

2

2.5

3

Recency mean - S as control, In-terval as experimental

Interval as control, S as experimental (mean for each section)

15 and 1S

primacy mean middle meanrecency mean

0.71 0.29 0.39

15 and 2S

primacy mean middle meanrecency mean

0.86 0.46 0.25

15 and 3S

primacy mean middle meanrecency mean

0.79 0.42 0.57

15 and 1S 15 and 2S 15 and 3S2.52.62.72.82.9

33.13.23.33.43.5

Primacy mean - Interval as control, S as experimental

15 and 1S 15 and 2S 15 and 3S0

0.5

1

1.5

2

2.5

Recency mean - Interval as control, S as experimental

Standard deviation

Appendix ix Mann Whitney Calculations

1. To determine whether the alteration of variables had an effect on the Primacy effect.

2. To determine whether the alteration of variables had an effect on the Primacy effect.