ABSTRACT
False memory is when individuals remember events differently from the way they occurred and sometimes even remember events that did not happen. Using this knowledge and by using visual aids, the study hypothesized that stress increases the occurrence of false memory. Most of the research on this topic shows that stress increases the formation of false memories in relation to word lists, but seldom does any research talk about the relation of stress and visual memory. Surveys, which included a picture and description, were carried out during the experiment and were filled out by 50 participants. The data supported the study’s hypothesis and showed that the participants who were shown a stress-inducing video formed more false memories than the control group, who were shown a neutral video. The results of this study were statistically significant as the p-value was 0.005147. This implies that people who are under stress are more likely to form false memories. This finding is important in relation to eyewitness testimonies, as it may lead to people getting wrongfully convicted.
INTRODUCTION
Memory is not like a video recorder as it does not accurately record everything that happens; in fact, memories are altered over time. False memory refers to when individuals remember events differently from the way they occurred and sometimes even remember things that did not happen. It can range from incorrectly remembering where someone left your car keys to falsely remembering the details of a crime. False memory can be caused by a variety of factors like misinformation and misattribution of the original source of the information. Existing knowledge and other memories can also interfere with the formation of a new memory, causing the recollection of an event to be mistaken or entirely false (Cherry, 2019).
Elizabeth Loftus, a contemporary psychologist, has shown through her extensive research on false memory that suggestion can induce false memory as well. She has also shown that false memories become stronger over time. In one of the earliest studies that aimed to create false memories, Loftus used the \”lost in the mall\” technique (Loftus, 1997). In this study, the subjects were told that the researchers had spoken with their parents and had learned about some events from their childhood. The subjects were narrated four stories out of which three were true and one was crafted by the researchers. The false memory was that the subject had been lost in a mall or a department store and that they had been eventually found and returned to their parents. After being interviewed in the following weeks, 25% of the participants had clear memories of this fictional event (Laney and Loftus, 2013).
An area adversely affected by false memory is eyewitness testimony. Elizabeth Loftus focused on the influence of (mis)leading information, including both visual imagery and wording of questions. In 1974, Loftus and Palmer conducted an experiment to see the effect of the language used on eyewitness testimony (Loftus and Palmer, 1974). They showed the subjects videos of traffic accidents and asked them to estimate the speed of the vehicles. The question they asked the subjects was \”About how fast were the cars going when they smashed/collided/bumped/hit/contacted each other?\”
The verb used altered the participants\’ perception of how fast the vehicles were traveling. The researchers attributed this to either response-bias factors which imply that the misleading information given might have influenced the answer a person gave but did not create a false memory, or altered memory representation which implies that the verb changed a person\’s perception of the accident and caused them to memorize it. Thus, a false memory was formed.
To determine if the second explanation was true, the group conducted another experiment. A week after the original experiment was conducted, the subjects were brought back and asked if there was any broken glass in the video(there was no broken glass in the video). Out of those who were asked how fast the cars were going when they \’smashed into\’ each other, a greater number of people reported having seen glass than those who were asked how fast the cars were going when they \’hit\’ each other. The results from the second experiment suggest that this effect is not just due to a response-bias, since leading questions actually altered the memory a participant had for the event (McLeod, 2014).
In another study conducted by Payne et al. in 2010, researchers studied the effect of stress on false memory (Payne, Jackson, Ryan, Hoscheidt, Jacobs, and Nadle, 2010). In this study, 66 college students were read a list of words related to sleep (the word ‘sleep’ was not on the list). The students were asked a few minutes later if ‘sleep’ was on the list and 60% of the students said yes. Later, they requested half the students to give an impromptu presentation, before taking the test, which was meant to induce stress in the students. This time, nearly 80% of the participants incorrectly recalled that ‘sleep’ was on the list, which was significantly more than the previous 60% of the students who were not induced to feel stressed.
Therefore, the existing research on false memory has indicated that stress makes people more likely to form false memories. While reviewing the literature available on this subject, the researcher did not come across any study that assessed the impact of stress on visual false memory through the use of pictures and descriptions. Hence, this study aims to measure whether stress increases the occurrence of visual false memory by measuring the number of false statements each participant wrote when presented with the task of recalling details from an image.
METHOD
2.1 PARTICIPANTS
The participants of the study were men and women from New Delhi, Mumbai, Noida, Gurgaon, as well as New York and Singapore. The participants’ ages ranged from 11 to 80, and they were members of various religions and ethnicities.
The total number of people who filled out the initial survey was 132 out of which
94 people agreed to fill out a follow-up survey. Those 94 people were randomly
assigned to the control and experimental groups using a random list generator after
balancing for extraneous variables like age. The mean age of the participants was 25.6 years and the standard deviation was 15.7467 years. None of the participants were blind or deaf and they were all fluent in English.
Out of the 94 people, a total of 50 people filled out the follow-up survey. 24 people belonged to the experimental group and 26 belonged to the control group.
2.2 MATERIALS
This experiment used three surveys in total: the initial survey that was used to familiarize the participants with the picture, the follow-up survey for the control group, and the follow-up survey for the experimental group. (See Appendix)
The surveys were created on Survey Monkey(www.surveymonkey.com). The initial survey started by asking the participants their demographic details, which were followed by a neutral video of people walking on a street (
). This was followed by a picture of a busy baggage carousel that was found on Google Images.
The follow-up survey for the control group contained a neutral video of cars driving by on a highway (
). The follow-up survey for the experimental group, on the other hand, contained a stress-inducing video of a family of ducks crossing a busy highway (
). Both surveys contained questions about the image that was shown in the previous survey.
The participants were sent the link to the survey via social media, and they needed a device with an internet connection, like a smartphone or a laptop, to take part in the study.
2.3 PROCEDURE
The research was conducted using surveys. In the initial survey, the participants were first informed about the purpose of the survey, which was a study on memory, how long the survey would take, that there would be a follow-up survey as well and they could opt out of the survey if they wished to.
They were then asked about their demographic details (name and age). This was followed by a filler task: a neutral video of people walking on a street. This video was shown as a control to the stress-inducing video to get the participants in a neutral state of mind. They were then asked how they felt after watching the video and a few other questions about the video, which were not evaluated. Then they were shown a picture of a busy baggage carousel in an airport.
Next, they were made to read a description of the picture with some false information to see if written cues changed people’s perception of the image. They were then asked to write a description of the picture, which was not used in the evaluation.
Two days later, the control group and the experimental group were sent their follow up surveys separately. The follow-up surveys for both groups were very similar, in both surveys, the participants were asked questions about the picture like, “What was the color of the canoe?” and “How many families did you see in the picture?”. The participants were even given space to write any other details they remembered about the image from the initial survey. But in the follow-up survey for the control group, these questions were preceded by a neutral video of cars passing by, and in the follow-up survey for the experimental group, these questions were preceded by a video of ducks crossing a busy highway, which was meant to make the participants feel stressed or anxious. This feeling of stress or anxiety was the independent variable in the study.
Once the participants filled out the follow-up survey, their responses were analyzed and points were given for every false statement. The number of false statements made by each person was the dependent variable. However, points were not given for simply forgetting. The points were then added to find the number of false statements per person. This was referred to as the false memory score (FM score) of the participant. The FM scores of each participant were added and the sum was divided by the number of participants to give the mean FM score per group. This process was performed for the control group and experimental group separately.
RESULTS
The mean FM score for the control and experimental groups was 3.68 and 4.92, respectively.
The standard deviation of the control and experimental groups was 1.44 and 1.82, respectively.
The standard error of the mean of the control and experimental groups was 0.29 and 0.36, respectively.
An unpaired one-tail t-test was done and the t-score was calculated to be 2.671.
The p-value was calculated to be 0.005147.
Fig. 1: Mean of FM scores of the control and experimental groups.
Fig. 2: Standard deviation of the control and experimental groups
Fig. 3: Standard error of the mean of the control and experimental groups.
DISCUSSION
The experiment was conducted to study whether stress increases the incidence of visual false memory. This hypothesis was supported by the results of the surveys as the p-value of the results was less than 0.05 and was, in fact, 0.005147, which showed that the results were statistically significant and the null hypothesis was rejected. The experimental group, which was exposed to the independent variable, the stress-inducing video, had a higher number of false statements on an average than the control group, who were induced to feel a neutral emotion.
The mean FM score of the experimental group was 4.92, and that of the control group was 3.68. This means that the people who were exposed to stress, on average, wrote more false statements about the picture they were shown in the initial survey than those who were not shown the stress-inducing video.
The results of this experiment are similar to the results of the experiment conducted by Payne et al. (Payne, Jackson, Ryan, Hoscheidt, Jacobs and Nadle, 2010) In this study, a list of words was read to college students, after which half of the participants were made to give an impromptu presentation to induce stress. The half which gave the presentation formed more false memories about the list than the half that was not exposed to stress. Based on the findings of their experiment, the researcher predicted that stress would increase false memory. While Payne et al. studied the effect of stress on the false memory related to a list among college students, the researcher of this study tested the effect of stress on visual false memory on people from the ages of 13 to 80.
However, this experiment had its limitations as well. Since the surveys were sent to the participants online, there was no way to control situational confounding variables such as the environment in which the participants took the survey. Even the device on which they filled out the surveys differed from participant to participant, which could also be a confounding variable. Since the participants filled out the survey on their own, any additional questions they had could not be answered by the researcher. There was also no way to control the existing stress levels of the participants or to know whether they were already stressed. The sample size was small since some participants decided to not take part in the research at the last moment, which brought the sample size to 50. The fact that many people withdrew might also mean that the people who responded to both surveys might have a similar mindset. Due to this, random selection and random assignment were not as effective.
It was also noted that older participants on average had a higher FM score although it was not statistically significant, which is shown in the following graph:
This study can be impactful as many innocent people go to jail because of false memories of eyewitnesses. In some cases, eyewitnesses are experiencing stress as they try to recall the events of a crime they witnessed. In other instances, the police may use high-pressure interrogation tactics, which also have the potential to lead to false memories as seen in this study. Thus, it is important to determine the extent to which stress impacts false memory. People also need to be made aware of the circumstances under which false memories are formed to possibly avoid the creation of false memories. False memory affects everyone, thus research on this topic is not just important due to its role in eyewitness testimonies but also due to its role in everyday life.
4.1 FUTURE EXPERIMENTS
While this experiment showed that stress increases false memories, experiments should be conducted in the future to evaluate the effect of age on false memory to see if the trend seen in this experiment is significant or not. There should also be experiments conducted on how to control or prevent false memories. Further research on how to distinguish between true and false memories would also be beneficial. This would help reduce the creation of false memories in eyewitness testimonies and also would help to differentiate between true and false memories, thereby reducing the number of people who go to jail due to false accusations.
If this study were redone, it should be conducted in person rather than online, and the surveys should be provided to participants on the same type of device so as to reduce situational confounding variables. This would also make it possible to answer any questions the participants might have in real-time. The sample size taken should be expanded, including people of various ages and ethnicities. The stress levels should also be measured more efficiently by taking participants’ biological responses into account.
CONCLUSION
To conclude, stress increases the occurrence of false memories. The results of this study show that when stress is induced in people, they are more likely to make false statements. Therefore, it is important to prevent placing eyewitnesses of crimes in highly stressful situations as they might make false statements about the crime.
REFERENCES
- Cherry, Kendra. “How cognitive biases influence how you think and act.” Verywell Mind (2019).
https://www.verywellmind.com/what-is-a-false-memory-2795193
- Loftus, Elizabeth F. “Creating childhood memories.” Applied Cognitive Psychology: The Official Journal of the society for Applied Research in Memory and Cognition 11, no. 7 (1997): S75–S86.
- Loftus, Elizabeth F., and John C. Palmer. “Reconstruction of auto-mobile destruction: An example of the interaction between language and memory.” Journal of Verbal Learning and Verbal behavior 13, no. 5 (1974): 585-589.
- Laney, Cara, & Elizabeth F. Loftus. “Recent advances in false memory research.” (2013): 137-146 https://journals.sagepub.com/doi/full/10.1177/0081246313484236#bibr40-0081246313484236
- McLeod, S. A. “ Loftus and Palmer.” Simply Psychology (2014). 23-24 https://www.simplypsychology.org/loftus-palmer.html
- Payne, Jessica, Eric Jackson, Lee Ryan, Siobhan Hoscheidt, Jake Jacobs and Lynn Nadel. “The impact of stress on neutral and emotional aspects of episodic memory.” Memory 14, no. 1 (2006), 1-16, DOI: 10.1080/09658210500139176
SUPPLEMENTARY CONTENT
APPENDIX
Survey 1:
The following video of people walking on the street was shown to the participants:
Follow up survey (experimental group):
The following video of ducks crossing a busy highway was shown to the participants:
Follow up survey (control group):
The following video of cars passing by was shown to the participants:
Nitya is a senior at Delhi Public School R. K. Puram, New Delhi, India. She is very interested in psychology and human behaviour. She\’s the captain of her school soccer team. She hopes to study Cognitive Science in college.