Memory

AUTOBIOGRAPHICAL MEMORY
Charles P. Thompson

DEVELOPMENT OF
Patricia J. Bauer Rebecca M. Starr

GRAPHICS, DIAGRAMS, AND VIDEOS
Priti Shah

IMPLICIT MEMORY
Henry L. Roediger III Lisa Geraci

MENTAL MODELS
Gabriel A. Radvansky
David E. Copeland

METAMEMORY
Gregory Schraw
John Nietfeld

MYTHS, MYSTERIES, AND REALITIES
Elizabeth J. Marsh

STRUCTURES AND FUNCTIONS
Peter E. Morris

AUTOBIOGRAPHICAL MEMORY

In the early twenty-first century there is general agreement among memory researchers that memory consists of a number of distinctly different types of memory rather than one single memory. A brief overview of the major divisions in memory will help put autobiographical memory in context. Philosophers have long made a distinction between knowinghow (e.g., knowing how to ride a bicycle) and knowing what (e.g., knowing what a bicycle is). Modern research has verified the distinction between these two types of memory, and they are currently called procedural or implicit memory (knowing how) and declarative or explicit memory (knowing what). In 1972 Endel Tulving divided declarative memory into semantic and episodic memory. Semantic memory, because it contains general information such as facts, names, and important historical dates, could be described as a person's knowledge of the world. Episodic memory refers to a person's memory of events.

Autobiographical memory is a large and important subset of episodic memory containing those events that constitute the story of one's life. In the words of Katherine Nelson, autobiographical memory is "specific, personal, long-lasting, and (usually) of significance to the self-system. Phenomenally, it forms one's personal life history" (p. 8). If the first meeting with a loved one involves going to a movie, that event stands a good chance of becoming part of autobiographical memory. Other occasions on which movies are attended, however, will be remembered for a short time but probably will not become part of autobiographical memory. Instead, those events will contribute to generic memory. Generic memory contains memory for frequently occurring events such as brushing teeth or going to a movie. When asked about such events, it is unlikely that a specific instance of toothbrushing or going to a movie will be remembered.

The Organization of Autobiographical Memory

Autobiographical memory is organized as nested clusters of events that are all highly interconnected. Take the memory of a lawyer as a hypothetical example. Under the topic of school, that person would find events for elementary school, secondary school, college, and law school. Nested under each of those categories would be the events for each year (e.g., sophomore in college). Under the category of sophomore in college would be the events for each semester, which, in turn, would be grouped in categories such as academic events (e.g., classes), jobs, and friends. All these autobiographical events would be accessible in a number of ways. A particular event might involve a certain year in college, a particular job, and certain friends. That event could be accessed when thinking about school, friends, or jobs.

The topic of school is just one example of the many topics that have many subcategories. Other such topics include marriage, jobs, and military service. Just like the clusters of events nested under topics, the topics also are highly interconnected. The end result is a memory system that has the ability to retrieve the memory of a particular event from a large number of starting points. The most obvious example of the power of autobiographical memory to retrieve events is involuntary memory–memories that just pop into mind. In a 1998 article Dorthe Berntsen described her studies of involuntary memories, which showed that people average six to eight such memories every day.

Memory for Autobiographical Events

Remembering an autobiographical event usually involves both retrieving the content of the event (remembering what) and placing it in time (remembering when). Of course, memory for both fades over time. Autobiographical memory can be either reproductive or reconstructive. When it is reproductive, virtually all the details are retrieved from memory. When it is reconstructive, a few major points are retrieved from memory and the rest is constructed from generic memory. People are very good at reconstructing memory from generic events, and they are usually not aware that they are doing so. One of the consequences is that memory for old events is often wrong. Sometimes the error is minor and sometimes it is not.

Memory researchers have shown that memory for the content of the event gradually changes from being almost entirely reproductive to being, after about a year, almost entirely reconstructive. By contrast, memory for when an event occurred is almost always entirely reconstructive.

There are three additional distinctive characteristics of memory for autobiographical events. First, as time passes, the number of events that can be recalled drops off rapidly at first and then more slowly–a negatively decelerating curve. Second, older people show what David C. Rubin and his colleagues called a "reminiscence bump." Older people recall more events for the period when they were in their twenties than predicted by the negatively decelerating memory curve. Typically, many important life events (such as college graduation, marriage, and children) occur when people are in their twenties. Research has shown that the reminiscence bump can be attributed to these important life events. Third, almost all people show infantile amnesia. When people are asked to recall events from their childhood, they usually cannot recall events prior to age three. Not only are they unable to recall memories before age three, but the number of memories retrieved between ages three and six is also markedly below the number available after that period. Infantile amnesia is an intriguing puzzle because researchers have shown that children under age three can report details of isolated specific events and, most important, can remember them for up to two years. There is a growing consensus that the answer to the puzzle may lie in the development of autobiographical memory.

The Development of Autobiographical Memory

By the early twenty-first century there was considerable evidence that children learn how to talk about memories with others. They learn how to tell their life stories as a narrative. This is the social interaction view of autobiographical memory. This view proposes that infantile amnesia is overcome when children learn how to retain their memories in a recoverable form by turning them into narratives.

One strong source of support for the social interaction view has been the investigation of mother-child discussions of past events. These discussions can be classified as narrative or pragmatic. The narrative conversations focused on what happened when, where, and with whom. The pragmatic conversations used memory to retrieve specific information such as "Where did you put your book?" Children of mothers who used the narrative type of discussion remember more about the events than children of mothers who used the pragmatic type of discussion.

Autobiographical Memory as an Expert System: Implications for Learning

Experts learn new material in their field much faster than novices, and they retain that material much better as well. The reason for their outstanding performance in learning and memory is that they have a highly organized and detailed memory for their area of expertise. This allows them to relate new material to one or more pieces of information that they already know. Metaphorically speaking, they have many potential pegs on which they can hang new information. When they have to retrieve the new information, they can follow a well-beaten path to that information.

Autobiographical memory is also a highly organized and detailed memory. When it is possible to relate new information to life events, autobiographical memory functions in the same way as an expert system. The new information will be learned faster and remembered better than information that cannot be related to life events (or to another expert system).

Life Is Pleasant–and Autobiographical Memory Makes It Better

In studies of subjective well-being conducted around the world, people generally report that they are happy with their life. In the United States, this positive feeling is found in people with physical disabilities, people with mental illness, low-income people, minorities–in short, it is found for virtually all categories. Research on autobiographical memory shows two sources for this positive feeling of well-being. First, life events are generally pleasant with positive events occurring roughly twice as often as negative events. This is true for childhood memories, involuntary memories, and adult memories.

Second, the general level of pleasantness typically is enhanced when remembering life events. That occurs because the emotion attached to the events fades over time but the emotion for unpleasant events fades much faster than the emotion for pleasant events. Thus, the overall emotional tone becomes more pleasant for autobiographical memory. The mechanism responsible for this change appears to be the rehearsal (thinking about or talking about) of pleasant events.

For most people, autobiographical memory is a very positive and useful part of memory. It is equivalent to an expert system and therefore can be very helpful in learning new material. Most important, it holds the story of one's life. That story is typically very pleasant and, because negative emotions fade rapidly, becomes more pleasant as time passes. People's lives would be much reduced without their access to autobiographical memory.