Thursday, April 13, 2017

False Memories

This is an essay I wrote for a class at Maryland.

INTRODUCTION

Each of us remembers an event or events which none of our friends and relatives remember. You might remember getting lost in a mall while on a family trip or witnessing an accident or, like I did recently, taking a group photograph at a friend’s wedding. However, your friends and family remember something completely different about the day of the event and they all agree on what happened. You think all your friends just have very poor memories and they must have forgotten the event. But, chances are, you are the one who doesn’t remember what happened. The event you so clearly remember might not have ever happened or might have happened very differently. What is happening here? Are you losing your mind or are your friends playing a prank?

False memory is a well studied psychological phenomenon of a person recalling something which either did not occur or occurred differently. When you remember taking a photograph at your friend’s wedding and no such photograph exists, you have created a false memory somehow. In this essay, I will discuss some studies which show how easy it is to acquire false memories. Studying false memories can shed light on how the human brain stores and retrieves memories.

When false memories begin influencing the orientation of a person’s life, the condition is called false memory syndrome (FMS). Though it is not recognised as a psychiatric illness, FMS can affect the “identity and relationships” of a person [1]. In some cases, the whole identity of a person can change because of a false memory of a traumatic experience. Understanding this phenomenon will help us understand ideas about identity and consciousness. Neurological study of patients suffering from FMS can help unlock secrets of the memory creation and storage process.

The concepts of false memory and false memory syndrome are close related to the phenomenon of confabulation which is the process of creating false memories without the intention to deceive. There are profound legal issues related to confabulation and false memories. How do you find out if a person has an intention of deceiving? How much do you trust eye-witness testimony? Which of the thousands of claims of repressed memories childhood sexual abuse do you believe? These are important questions for the judiciary and for psychologists trying to understand the human behaviour. Another related effect is the source-monitoring error. This happens when you incorrectly attribute the source of a memory/information. You might attribute a fact that you know to a book when you actually saw it in a video.

In the next few sections, I will explore some of these phenomena and present some experiments which might make you question every memory you have.


HOW CAN FALSE MEMORIES BE CREATED?

Scientists have discovered several ways of creating false memories in people. Photos, speech, or text have all been used to create these false memories. I will describe some very simple examples of memory distortion and false memory implantation. First, I discuss a very influential study by Loftus et al. which shows how language can create false memories.

Recalling incorrect information due to language of the question
In [7], Loftus and Palmer showed videos of cars hitting each other to a few subjects. They then asked the subjects to estimate the speed of the cars. They found that using different words to describe the accident led to different estimates of the speed. For example, the question “About how fast were the cars going when they smashed into each other?” [7] led the subjects to estimate the speed of the cars higher than when using the verbs bumped, collided, contacted, and hit. They observed similar trends for the question “Did you see any broken glass?” [7]. This showed that human memories are extremely susceptible to suggestion and can be influenced by changing just a single word.

Similar studies with changing an article (“Did you see a stop sign?” vs. “Did you see the stop sign?”) or an adjective (“How tall was the basketball player?” vs. “How short was the basketball player?”) in the question led to differing accounts of events [2]. This is because using a particular word instead of others causes subjects to create certain presuppositions which colour their judgment about the events in questions. This raises questions about the reliability of the recalled memories. Dr. Loftus has written extensively about the unreliability of memories recalled through prolonged searches for them [6]. She says that the rise in cases of child abuse involving repressed memories is alarming. The possibility of these recalled memories actually being false memories should not be ignored. In some cases, the psychiatrists themselves might be responsible for creating these false memories in the subjects through techniques like age regression, hypnosis, guided visualisation, etc.

Another study involving the use of language for creating false memories dealt with remembering lists of words.

False memories through lists
The authors of [8] show that even college students who are “professional memorisers” can falsely remember words not present in a list which they were asked to remember. Subjects were given lists of words related to a concept (nonpresented word), without explicitly stating the concept in the list. For example, a subject might have been given the list bed, alarm, rise, dream, ... etc. All these words are usually associated with sleep but the word sleep is not explicitly mentioned in the list. The recall rate of the nonpresented word was very high in the subjects. This led the authors to conclude that all memory is constructive in nature. This was in contradiction to the theory of reproductive and reconstructive memories proposed by Bartlett and Burt [4] which was the prevalent belief at that time. The theory said that list learning paradigms come under rote reproduction which causes few errors. On the other hand, rich material like stories encourages constructive processes which form associations and connection between different parts of the material. Retrieval of these memories leads to more errors. By showing incorrect recall of words in lists, the authors of [8] showed that the distinction between reproductive and reconstructive memories was ill-founded.

Obviously, language is not the only source of false memory creation. The next section describes a study which shows that visual information can also lead to false memories.

Photographs with news articles
Photographs accompanying a news article can help cement the content better [10]. In their experiments, authors of [10] showed newspaper headlines to subjects. Some of these headlines were accompanied by photos which were tangentially related to the headline. Also, some of these headlines were false, that is, the events described in the headlines had never actually happened. After reading the headlines and seeing the photographs, where present, the subjects were asked whether they remembered the events described in the headlines. The authors found that photos mattered. For both true and false headlines, people remembered more of the events described by the headlines which were accompanied by photographs. In remembering the events described by the false newspaper headlines,people had created false memories of the events. And they created more false memories for the events which had photos associated with them. The authors claimed that this could be explained by Rubin’s basic systems approach to memory [9]. This theory says that memory is a result of multiple systems and subsystems - visual, auditory, language etc. - which interact and reinforce each other. Providing stimulus to multiple subsystems leads to reinforcement of each subsystem and that helps in creating stronger memories.

From all these ways of creating false memories, we can clearly say that the study of the phenomenon of false memory can help in answering several questions about the human brain and how it encodes, stores, and retrieves information.

However, false memories are not just a personal phenomena. Whole societies and communities can create false memories among the community. Similar false memories can be shared by many people or the whole community.

Collective False Memory
Very recently in a lecture, someone mentioned that Jimmy Carter held a nuclear engineering degree. A lot of people in the audience agreed with this fact. However, on checking, I found out that he actually did not hold a nuclear engineering degree. This is an example of a collective false memory - a memory shared by multiple people which is incorrect. This phenomenon is also called the ‘Mandela’ effect due to several people around the world incorrectly remembering that Nelson Mandela died in the 1980s. Social reinforcement of false memories is held to be one of the leading causes of collective false memory. Suggestibility of people under similar circumstances can also lead to the creation of collective false memories.


IMPLICATIONS FOR AI RESEARCH
The study of false memories can give important clues as to how human memory is encoded, stored, manipulated, and retrieved. Studying retroactive interference and the misinformation effect [3] can help us in understanding the encoding process for memories. Retroactive interference is the process by which information presented later interferes with the information already stored in the brain. This causes the earlier information/memories to be modified or completely erased. This effect can be clearly seen at play during several studies which create false memories (e.g. the case of false memory creation through language.). Neurological studies while conducting false memory experiments can reveal the areas of the brain being affected by the incorrect information.

False memories are also related to imagination. In [5], the authors demonstrated “imagination inflation” - the phenomenon that simply imagining a childhood event increases the confidence of the subjects that that event actually happened. Studying this further might help us understand how we imagine, what is the process of forming pictures in the “mind’s eye”, and how is imagination related to memory.

Studying false memory, like any other peculiar human behaviour can provide important information about the human brain and the mind.


REFERENCES
[1] https://en.wikipedia.org/wiki/False memory syndrome.
[2] https://en.wikipedia.org/wiki/False memory.
[3] https://en.wikipedia.org/wiki/Misinformation effect.
[4] Frederic Charles Bartlett and Cyril Burt. Remembering: A study in experimental and social psychology. British Journal of Educational Psychology, 3(2):187–192, 1933.
[5] Maryanne Garry, Charles G Manning, Elizabeth F Loftus, and Steven J Sherman. Imagination inflation: Imagining a childhood event inflates confidence that it occurred. Psychonomic Bulletin & Review, 3(2):208–214, 1996.
[6] Elizabeth Loftus. Memory distortion and false memory creation. Bulletin of the American Academy of Psychiatry and Law, 24(3):281–295, 1996.
[7] Elizabeth F Loftus and John C Palmer. Reconstruction of automobile destruction: An example of the interaction between language and memory. Journal of verbal learning and verbal behavior, 13(5):585–589, 1974.
[8] Henry L Roediger and Kathleen B McDermott. Creating false memories: Remembering words not presented in lists. Journal of experimental psychology: Learning, Memory, and Cognition, 21(4):803, 1995.
[9] David C Rubin. The basic-systems model of episodic memory. Perspectives on Psychological Science, 1(4):277–311, 2006.
[10] Deryn Strange, Maryanne Garry, Daniel M Bernstein, and D Stephen Lindsay. Photographs cause false memories for the news. Acta psychologica, 136(1):90–94, 2011.