The order of the words in each list may also be a confounding variable. This confounding variable was reduced by having the order of the words on each list randomly selected
The adjectives chosen in this experiment may also affect the recall of the words because some adjectives may be easier to be remembered than others due to the length and the definition of the adjectives. This was controlled by having no more than two syllables for each adjectives and the adjectives used in this experiment was fairly common and familiar for students in Year 11-13.
Conditions
In this study, there will be three conditions; a resting condition in which the participants will be resting for a period of 5 minutes known as the 5-minute interval, and the synonyms condition in which the participants will be asked to learn 10 synonyms of the original list of adjectives during the 5-minute interval. The third condition is the antonym condition in which the participants will be asked to learn 10 antonyms of the original list of adjectives during the 5-minute interval.
Participants:
Target population: Shrewsbury International School Year 11-13
Sample size: 30 students
15 females, 15 males
There are three conditions so10 students will be assigned to each condition to provide a representative sample for each group.
Sampling method:
Opportunity Sampling is selected because it is convenient and less time-consuming. The experimenter will choose the participants that fits with the target population.
(Continue)
Apparatus:
-
Standardized instructions 1 for condition 1 (see Appendix)
-
Standardized instructions 2 for condition 2 and 3 (see Appendix)
-
Original list of adjectives (see Appendix- Word List 1)
-
Synonym list of adjectives (see Appendix- Word List 2)
-
Antonym list of adjectives (see Appendix- Word List 3)
- Writing utensils
- Sheets of A4 paper
- Stopwatch
Procedure:
- Each participant picks a number from 1 to 3. This will be the condition they are allocated to.
- Participants are allocated to conditions in this way until conditions are complete (10 participants per condition).
- The participants allocated to condition 1 then follow this procedure.
Condition 1 (Resting Condition)
- Seat the participants on a chair with a desk in a classroom.
-
Give them the standardized instructions to read. (See Appendix)
- Give the participants the standardized instructions with the number 1 written on the bottom right hand side of the page.
-
Have the participants read the given instructions. Say, “You are to read the instructions given to you in front of you.”
-
Ask the participants whether they understood the instructions and assist the participants if there are any questions. Ask, “Do you have any questions?” and Say “Remember, if you feel distressed or you want to leave, you have the right to do so. Just raise your hand and inform me to discontinue the experiment.”
-
Hand them Word List 1 and instruct the participants to learn the 10 adjectives perfectly. (See Appendix) Ask the participants to inform the experimenter when they learned the words perfectly. Say, “Please learn the given list of adjectives perfectly and inform me when you finished.”
- Take Word List 1 away from the participants and give them a piece of paper and writing utensil to write down the 10 adjectives. This is to test whether or not the participants have memorized the 10 adjectives. If the participants did not learn the adjectives perfectly, go back to stage f. If they learned it perfectly, continue to stage h.
- Prepare a stopwatch and time 5 minutes.
-
Ask them to sit still for 5 minutes without any other distraction. Say, “Now, please rest for 5 minutes. You will be informed when the 5 minutes are up.”
-
After 5 minutes, say, “Your 5 minutes are up.”
Condition 2 and 3 (Synonym and Antonym Condition)
- Seat the participants on a chair with a desk in a classroom.
-
Give them the standardized instructions to read. (See Appendix)
-
Give the participants in condition 2 and the participants in condition 3 the standardized instructions with the number 2 written on the bottom right hand side of the page.
-
Have the participants read the given instructions. Say, “You are to read the instructions given to you in front of you.”
-
Ask the participants whether they understood the instructions and assist the participants if there are any questions. Ask, “Do you have any questions?” and Say “Remember, if you feel distressed or you want to leave, you have the right to do so. Just raise your hand and inform me to discontinue the experiment.”
-
Hand them Word List 1 and instruct the participants to learn the 10 adjectives perfectly. (See Appendix) Ask the participants to inform the experimenter when they learned the words perfectly. Say, “Please learn the given list of adjectives perfectly and inform me when you finished.”
- Take Word List 1 away from the participants and give them a piece of paper and writing utensil to write down the 10 adjectives. This is to test whether or not the participants have memorized the 10 adjectives. If the participants did not learn the adjectives perfectly, go back to stage f. If they learned it perfectly, continue to stage h.
- Prepare a stopwatch and time 5 minutes.
- Condition 2
For the participants allocated in condition 2 which is the synonym condition, hand them Word List 2 with the 10 adjectives (See Appendix) and ask them to learn the list. Say, “Now you will be given a new list of adjectives to remember. You only have 5 minutes to learn all of them. You will be informed when the 5 minutes are up.” Use the stopwatch and give them 5 minutes.
Condition 3
For the participants allocated in condition 3 which is the antonym condition, hand them Word List 3 with the 10 adjectives (See Appendix) and ask them to learn the list. Say, “Now you will be given a new list of adjectives to remember. You only have 5 minutes to learn all of them. You will be informed when the 5 minutes are up.” Use the stopwatch and give them 5 minutes.
-
After 5 minutes, say, “Your 5 minutes are up.” Take the Word List 2/Word List 3 away from the participants in condition 2 and 3.
-
Prepare a sheet of paper and a writing utensil. Ask the participants in all conditions to write down the 10 adjectives from Word List 1 which they have learned it perfectly before. Say, “Now, please write down the 10 adjectives from the first list of adjectives that you were given to remember perfectly and were tested on it.”
-
Tell the participants that the experiment is finished and thank the participants for their cooperation. Say, “Thank you for your participation and cooperation. The experiment has now finished.”
- Debrief the participants by informing them that the experiment was a psychological experiment on interference on memory.
Debrief by saying, “You have just participated in a psychological experiment on forgetting in long-term memory. This experiment examines on retro-interference theory which indicates that later memories disrupt earlier memories. After learning the original list of adjectives, the participants were divided into three conditions in this experiment. Condition 1 is the resting condition which the participants rest for 5 minutes during the 5-minute interval. Condition 2 is the synonym condition which the participants were asked to learn a new list of synonyms of the original list of 10 adjectives. Condition 3 is the antonym condition which the participants were asked to learn a new list of antonyms of the original list of 10 adjectives. According to retro-interference theory, the more similar the new material to the original, the more the recall of the original list will decline. Therefore participants in the synonym condition will have higher level of forgetting due to greater interference. Retroactive interference also affected the recall of the participants in the antonym condition, though not as much as the synonym condition. Participants in the resting condition are least likely to be affected because no new material was given to them to learn. You have just participated in the (resting/synonym/antonym) condition. Thank you.”
Results
Descriptive statistics
First, the results table was generated showing the calculated measure of central tendency and the measure of dispersion for each condition (Resting, Synonym, and Antonym). This is shown below. The mean refers to the average number of adjectives recalled by participants in each condition. The mode refers to the most frequent number of adjectives recalled by participants in each condition. The median shows the central number of the total adjectives recalled by participants in each condition. The standard deviation measures the average deviation of the difference of each number of adjectives recalled from the mean. Please refer to the appendix for the raw data and calculations.
Table showing measure of central tendency and dispersion:
(Calculations- View appendix)
Graph:
Subsequently, an appropriate graph was constructed to show and compare the average mean of the number adjectives recalled in each condition. In this experiment, a bar graph was chosen.
Inferential statistics
The test chosen was the Mann-Whitney U Test. This investigation was a two sample test of difference, an independent measures design and the data was regarded as ordinal.
Test results (see appendix for calculations) show that the observed value of U was 14.5. The critical value of U was 27 (N1 = 10, N2 = 10 for a one-tailed test at P<0.05).
This is a directional hypothesis because earlier research by McGeoch and McDonald (1931) suggested that more retroactive interference would occur in the synonyms condition and evidence can be found in the findings of their research.
Discussion
Explanations of findings
The aim of this study was constructed based on the original research of McGeoch and McDonald (1931) and this present experiment was to replicate their experiment to examine interference theory of LTM. The aim of this study was also to investigate the strength of retroactive interference in LTM. The three conditions used to compare the results were the resting, synonym, and antonym. A directional hypothesis states that the group of participants that rested during the 5-minute-interval would significantly recall more adjectives from the original list than those who learned the synonyms during the 5-minute-interval. Findings of this experiment show that the synonym group recalled in average more adjectives than other two conditions. The test results also showed that the observed value of U, 14.5, was less than the critical value of U, 27. Therefore, the findings of this experiment are unlikely to occur due to chance or random miscalculation since the probability of the resting condition and the synonym condition occurring is 5% or less. For that reason, the null hypothesis is rejected and the experimental hypothesis is accepted.
The results table is generated to show the central tendency and dispersion between the resting condition and the synonym condition. The table showed that on the whole, the mean, mode, and median of the resting condition is significantly higher than the synonym condition. Moreover, the outcome of standard deviation of the synonym condition is higher than resting condition. This means that the results collected from the raw data (number of words which each participants remember) is more dispersed in the synonym condition.
Relationship to background research
The results of this experiment generated findings that strongly supports the results of McGeoch and McDonald. This experiment found that the number of adjectives recalled is most likely to be affected if a certain activity is occurring between the time interval of learning and time of recalling. McGeoch and McDonald examined many different activities including nonsense syllables and numbers whereas this experiment examined specifically on only three conditions. Similar to the original findings, the more similar information was fed, the more likely the recalling is to be affected. Thus, the synonym group of this research had the lowest recall rate of 6.4 average number of adjectives compared to the antonym, 7.4, and the resting condition, 8.7. The findings prove to be comparable to those of McGeoch and McDonald’s with 4.50 average recalls of ten adjectives in the resting condition, 1.25 in the synonym, and 1.83 in the antonym. This suggested that retroactive interference do occur and the more similar the later material, the greater the interference.
However, there are alternative explanations of LTM such as trace decay and retrieval failure. The trace decay theory explains forgetting in LTM in terms of automatic decay of memories over time. Still, this theory can be criticized since there is little evidence to support this. Retrieval failure theory suggests that if the memories are not accessible, it is not retrieved and will be forgotten.
Limitations and medications
The findings are based on laboratory experiments, thus, are set in an artificial conditions. The participants are removed from their everyday settings and the tasks participants are asked to perform may appear unrealistic. Such experiments have low ecological validity. However, laboratory experiment provides opportunity to control the effects of confounding variables; thus, there is a higher certainty about the cause and effect relationships between the independent variable and the dependent variable.
Deceiving the participants and not receiving their informed consent were considered as limitations. First, the participants were not fully ‘informed’ of all aspects of the research. However, a major problem with informed consent is the possibilities that the researcher will reveal their aim which would generate invalidate findings. Since they are not fully “informed”, the participants were being deceived. However, both the British Psychological Society and American Psychological Association agree that deception is unavoidable in certain cases. This was also dealt effectively by debriefing all participants after the experiment has ended.
Another limitation is that the participants might have understood the instructions differently. This was dealt by having an experimenter present to answer the participants’ questions if they had any and the participants were also given a sheet of detailed standardized instructions.
The stimulus of this experiment was also a limitation. The adjectives chosen in this experiment might also affect the recall of the words because some adjectives might be easier to be remembered and recalled than another. This is because some adjectives might have more significant meaning to certain participants or it might be due to the length and the definition of the adjectives This was dealt appropriately by having no more than two syllables for each adjectives and the adjectives used in this experiment was commonly understood by the Year 11-13.
.
Implications and suggestions for further research
The findings of this experiment are significantly useful and can by applied towards many aspects of learning and education. The findings suggest that the recall of the earlier learnt material can be affected by the later learnt material due to retrospective interference. The more similar the later material or task, the greater the interference and the higher level of forgetting. This can be applied in school and be implemented in daily teaching. Teachers may apply this theory by not giving similar materials for students to learn after they just learned the earlier material to reduce the likelihood of retrospective interference and forgetting. They could also teach different materials by using different approaches so the students will be able to distinguish the materials through different approaches learnt and they will not be confused. People can implement this concept into learning in everyday life to prevent them from forgetting in LTM.
There were only three independent variables tested in this experiment (resting, synonym, and antonym conditions) where as McGeoch and McDonald’s experiment examined six different independent variables. Therefore, this experiment could be improved by including more independent variables to be tested. For further research, this experiment could vary on the different types of materials being learnt such as numbers and face recognition. Forgetting, perhaps, will be different due to the content and the context of the materials learnt. Moreover, this research was based not only in Bangkok, but also based in a school. The experiment would be more credible if further research was done in different groups of people and different countries.
Appendix
Standardized Instructions
Please read the instructions carefully:
You will be given a word list of ten adjectives to remember. You must remember these ten adjectives perfectly in order to go on to the next stage. Please try your best to remember all ten adjectives as soon as possible.
When you are finished, please inform the experimenter and you will be given a writing utensil and a paper. The experimenter will test you by having you write down the ten adjectives.
You will then be asked to rest for five minutes. Please sit and rest quietly during this period of time.
Do not do anything until the experimenter instructs you to. Please listen to the experimenter carefully. If you feel anxiety or distressed during the experiment, you may ask the experimenter to discontinue the experiment. You have the right to do this anytime during the experiment.
If you have any questions after reading this instruction, please ask the experimenter.
1
Standardized Instructions
Please read the instructions carefully:
You will be given a word list of ten adjectives to remember. You must remember these ten adjectives perfectly in order to go on to the next stage. Please try your best to remember all ten adjectives as soon as possible.
When you are finished, please inform the experimenter and you will be given a writing utensil and a paper. The experimenter will test you by having you write down the ten adjectives.
You will then be asked to remember another list of ten adjectives. Please try to learn all of these in 5 minutes. You will be told when the time is up.
Do not do anything until the experimenter instructs you to. Please listen to the experimenter carefully. If you feel anxiety or distressed during the experiment, you may ask the experimenter to discontinue the experiment. You have the right to do this anytime during the experiment.
If you have any questions after reading this instruction, please ask the experimenter.
2
Word List 1
Happy
Nice
Humble
Clever
Thin
Crazy
Fast
Easy
Active
Weak
Word List 2
Joyful
Kind
Modest
Witty
Slim
Bizarre
Quick
Simple
Lively
Frail
Word List 3
Angry
Mean
Prideful
Stupid
Fat
Normal
Slow
Complex
Boring
Strong
Raw Data collected from participants: Shows the number of adjectives recalled by each participant in each condition
Calculations of Mean, Mode, Median, and Standard Deviation
Calculations of Mann-Whitney U Test
Project Brief Proposal Form
- Identify the aim of the research and state the experimental/alternative hypothesis.
The aim of this coursework is to partially replicate McGeoch and McDonald’s experiment (1931) to investigate interference theory of LTM and to assess retroactive interference theory in LTM. The experimental/ alternative hypothesis is the group of participants that rested during the 5-minute-interval would recall significantly more adjectives from the original list than those who learned the synonyms during the 5-minute-interval. Therefore, retrospective interference would occur greater in the synonyms group than the resting group.
- Explain why a directional or a non-directional experimental/alternative hypothesis has been selected.
The directional hypothesis has been selected because earlier research by McGeoch and McDonald (1931) suggested that more retroactive interference would occur in the synonyms condition and evidence can be found in the findings of their research. Therefore, this experiment is determined to investigate the retrospective interference in three different conditions and to examine whether the participants in the synonym condition would recall the least number of adjectives compared to other two conditions. Thus, this implies that greater retrospective interference does occur in the synonym condition.
- Identify the chosen research method (experimental, quasi-experimental, natural experiment, survey, observation, content analysis or correlational research) and, if appropriate, the design used.
The chosen research method is experimental because first of all, the original research is in the form of a controlled laboratory experiment. The design of this experiment is an independent measure. This is to avoid the order effects between the conditions.
- Identify the strengths and weaknesses of the chosen research method.
The strengths of laboratory experiments include enabling the experimenter to control the confounding variables which may affect the findings of the research. It is also easy to replicate and the experimenter is able to manipulate the independent variables to examine the dependent variable. This provides a high degree of certainty between the cause and effect.
The artificial setting of laboratory experiments is a weakness because it may generate demand characteristics and alter the way the participants behave. Therefore, findings of laboratory experiments may lack ecological validity. Another weakness is that the participants will be deceived because they are not “fully” informed about the aim of the research.
- Identify potential sources of bias in the investigation and any possible confounding variables.
Carrying out an experiment on one particular gender is a potential source of bias because the findings will be difficult to be generalized in another gender. One of the confounding variables is that it was an independent groups design. This means that each participant in each group experiences only one condition of the independent variable, therefore, controlling individual differences is left to chance. Another extraneous variable is that participants may understand the instructions differently.
The adjectives chosen in this experiment may also affect the recall of the words because some adjectives may be easier to be remembered than others due to the length and the definition of the adjectives. The target population of Year 10-13 in Shrewsbury International School of Bangkok is considered an extraneous variable because it cannot be generalized in other age groups or school.
- Explain what procedures will be adopted to deal with these.
Gender as a confounding variable will be dealt by having both boys and girls participating in this research rather than one gender. The problem of the independent groups design is dealt by randomly assigning to each condition which means that the participants will have an equal chance of being assigned to each of the conditions.
This was dealt by having detailed standardized instructions for all participants. If there was any question, the experimenter would be there to answer them.
This was controlled by having no more than two syllables for each adjectives and the adjectives used in this experiment was fairly common and familiar for students in Year 11-13.
The fact that this experiment would be conducted on students in Year 11-13 in Shrewsbury International School of Bangkok, the findings may not be able to generalize in the general population. However, this experiment is determined to examine specific group of students, in this case, the Year 11-13. It is also convenient and easy to get access to this target population.
- Select an appropriate level of statistical significance to be reached before the experimental/alternative hypothesis will be retained.
The experimental hypothesis will be retained if the probability of the results in the resting and synonym conditions occurring by chance is 5% or less.
- Identify any relevant ethical issues and identify the steps to be taken to deal with these.
Confidentiality is a relevant ethical issue that may arise in this experiment. If the experimenter collected personal details of each participant, participants might behave in a reserved or in a positive light due to effects of evaluation apprehension. In order to deal with confidentiality issue, no personal detail such as name and address will be taken.
Harming the participants is also an issue because some participants may feel uncomfortable in the environment or feel anxiety when they are asked to memorize many adjectives, therefore, the participants will feel distressed. To deal with this, when the participants receive their standardized instructions, there will be a statement telling the participants that if they feel uncomfortable or distressed, they can withdraw (leave) anytime they want. This statement will also be emphasized as the experimenter will also inform the participants that they have the right to withdraw if they feel distressed.
Deceiving the participants and not receiving their informed consent will be considered as limitations. Since they will not be fully “informed” about all aspects of the experiment in the beginning, the participants will be deceived. However, both the British Psychological Society and American Psychological Association agree that deception is unavoidable in certain cases. This will also be dealt effectively by debriefing all participants and informing the aim of the research after the experiment has ended.
Abstract
The aim of this coursework is to partially replicate McGeoch and McDonald’s experiment (1931) to investigate interference theory of LTM and to assess retroactive interference theory in LTM. Three conditions are used in this experiment. However, the statistical test will compare the resting condition with the synonym condition. The antonym condition will be discussed in relation to the other conditions.
The study was based on a laboratory experiment and used an independent measures design. The participants were sampled using opportunity sample. The sample consisted of 30 participants and the target population was Shrewsbury International School Year 11-13.
All participants were given standardized instructions and were told to learn a list of 10 adjectives. The participants in the first condition, which was the resting condition, were asked to rest for 5 minutes. The participants in the second condition, which was the synonym condition, were asked to learn another 10 adjectives that were synonyms to the original list of adjectives for five minutes. The participants in the third condition, which was the antonym condition, were asked to learn another 10 adjectives that were antonyms of the original list of adjectives for five minutes. After the 5 minutes, all participants were then asked to recall the original list of 10 adjectives by writing it down on a piece of paper.
The directional hypothesis is the group of participants that rested during the 5-minute-interval would recall significantly more adjectives from the original list than those who learned the synonyms during the 5-minute-interval. The results show that the participants in the resting condition recalled an average of 8.7 adjectives, those in the synonym condition recalled an average of 6.4 adjectives (this was significant at the 0.05 level), and those in the antonym condition recalled an average of 7.4 adjectives. Therefore, the results support the directional hypothesis because the participants recalled significantly more adjectives in the resting condition than the synonym condition.
As the results showed support to the hypothesis results, it can be concluded that retroactive interference do occur and the more similar the later material, the greater the interference and the higher level of forgetting. The findings of this experiment are significantly useful and can be implemented towards many aspects of learning and education. This can be applied in school and be implemented in daily teaching. People can implement this concept into learning in everyday life to prevent them from forgetting in LTM.
