What Is Episodic Memory?

An episodic memory is a memory of a specific event. Because each person has a different perspective and experience of an event, episodic memories of that event are unique to each person.

Closely related to this is what researchers refer to as autobiographical memory—memories of your own life history. As you can imagine, episodic and autobiographical memories play an important role in your self-identity.

How Episodic Memory Works

Imagine that you get a phone call from an old college friend. You spend an evening reminiscing about amusing moments from your days at school. Your memories of those specific events and experiences are examples of episodic memory. These memories provide you with a sense of personal history as well as a shared history with other people in your life.

Several parts of the brain work in concert to help you store and retrieve episodic memories: the temporal, parietal, and frontal cortices, diencephalon, and cerebellum. Practice, genetics, and experience all influence your ability to recall episodic memories.

Episodic vs. Semantic Memory

The term episodic memory was first introduced by Endel Tulving in 1972 to distinguish between remembering events from the past (episodic memory) and knowing factual information, which is known as semantic memory.

Semantic memory is focused on general knowledge about the world and includes facts, concepts, and ideas. Episodic memory together with semantic memory is part of the division of memory known as explicit or declarative memory.

Types of Episodic Memories

Episodic memories fall into a few main categories.

Specific Events

These involve memories of particular moments from personal history. Your first kiss, first day of school, a friend's birthday party, and your brother's graduation are all examples of episodic memories. In addition to your overall recall of the event itself, the episodic memory include the locations and times of the events.

Personal Facts

Knowing who was president the year that you got married, the make and model of your first car, and the name of your first boss are all examples of personal fact episodic memories.

General Events

Remembering what a kiss feels like is an example of this general type of memory. You do not remember each and every kiss you've ever shared, but you can recall what it feels like based on your personal experiences.

Flashbulb Memories

Flashbulb memories are vivid and detailed "snapshots" related to finding out particularly important news. Sometimes these moments might be highly personal, like the moment you found out that your grandmother had died.

In other cases, these memories might be shared by many people in a social group. The moments you found out about the 9/11 attacks or the Paris concert theater attacks are examples of shared flashbulb memories.

Examples of Episodic Memories

Some examples of episodic memories might include:

• What happened on your recent trip to Disneyland
• Where you were when you learned that a loved one had died
• Your old cell phone number
• Your first day at your job
• Your first date with your partner

Remember, each person's episodic memory of an event is entirely unique. Even other people who shared the same experience may have different recollections of what happened.

9 Properties of Episodic Memory

Research indicates that episodic memory carries nine attributes. Other types of memory feature some of these, too—but only episodic memories comprise all of them. Episodic memories:

1. Contain summary records of sensory-perceptual-conceptual-affective processing
2. Retain patterns of activation/inhibition over long periods
3. Are often represented in the form of (visual) images
4. Always have a perspective (field or observer)
5. Represent short time slices of experience
6. Are represented on a temporal dimension roughly in order of occurrence
7. Are subject to rapid forgetting
8. Make autobiographical remembering specific
9. Are recollectively experienced when accessed

Impact of Episodic Memory

Researchers have found that episodic memory can also be interdependent with semantic memory. On learning tasks, participants performed better when new information was aligned with prior knowledge, suggesting that semantic knowledge of a task provides a sort of framework for new episodic learning.

Participants were asked to remember the prices of grocery items. Those in the control group were better able to remember these prices when the new information was congruent with their existing episodic memories of grocery prices.

Amnesiac participants in the experimental group, however, performed much worse at remembering new information because they did not have access to episodic information from their past.

Conversely, researchers have also found that episodic memories also play a role in the retrieval of semantic memories. In experiments where participants were asked to generate lists of items in particular categories, those who were able to rely on episodic memories performed better than amnesiac participants who did not have access to episodic memories.

Studies also suggest that there are sex differences in episodic memory. Research has found, for example, that women tend to outperform men on tests of episodic memory function, particularly on verbal-based episodic memory. Studies also show that women are able to access these memories faster and date them more accurately than men.

How Damage and Disease Can Affect Episodic Memory

Aging and neurodegenerative diseases take an extreme toll on episodic memory. For example, a decline in the ability to retrieve this kind of memory is among the first signs of Alzheimer’s disease.

Other psychiatric conditions such as dissociative disorders, schizophrenia, and Parkinson's disease also feature deficits in episodic memory functions. However, such damage is difficult to assess because memories are difficult to induce and measure.

Likewise, traumatic brain injury, such as concussion, tends to impede episodic memory. Semantic memory appears to be less susceptible to this kind of damage.