Episodic Memory

Episodic memory is the mental record of personal experiences or nonpersonal events that have occurred at a specific time and place in the past. Episodic memory is distinct from semantic memory, which comprises accumulated knowledge of the world. Episodic memory for one's own life in particular is termed “autobiographical memory.” Episodic memory is typically declarative, meaning that an individual can describe the event. When generating episodic memories, people often experience self-knowing conscious recollection of their past, or autonoetic awareness. An episodic memory may also be experiential whereby an individual is able to reexperience aspects of the original episode, a phenomenon that Endel Tulving referred to as “mental time travel.” This type of internal experience may trigger imagery and/or emotional reactions.

One universal feature of lifelong episodic memory is the “reminiscence bump,” an increase in the number of memories stemming from young adulthood. Adults also tend to lack episodic memories from the first few years of life, a phenomenon known as childhood amnesia. Finally, episodic memories can be involuntary, summoned to consciousness without effortful intention. Involuntary autobiographical memories can be vivid and occur on average between two and five times every day.

Engaging episodic memory makes significant demands on multiple cognitive systems, including attention, executive control, self-reflection, imagery, and semantic understanding. Recalling the past is therefore associated with a disparate brain network including, but not limited to, the medial and ventrolateral prefrontal, medial, and lateral temporal and posterior cingulate cortices; the temporoparietal junction; and the cerebellum. In particular, memory activity is associated with the hippocampus and immediately adjacent systems, the removal of which has a devastating impact on memory function. The act of recalling episodic musical memories is associated with right lateralized activity within this network, as distinct to the pattern observed when people perform a semantic music memory task.

Episodic memories have a normal forgetting pattern over short periods of time, a finding indicative of the everyday experience of a person walking into a room and forgetting why they are there. All memories are constructions and hence may be inaccurate and liable to distortion, for example, remembering one's part in an event as more important than it actually was. A more consistent and permanent breakdown of episodic memory, an ability to form new memories and/or to recall old ones, is indicative of amnesia and Alzheimer's disease.

A well-known memory experience from the music psychology literature is the “Darling, they are playing our song” phenomenon. This example can illustrate the various components of memory outlined above. First, if an individual simply recognizes “their song,” this would mark an occurrence of semantic memory.

If hearing the song leads the person to consider world events around the time when the song was recorded, they may use episodic memory. If the individual, perhaps moved by romance, begins to mentally relive the personal events surrounding “their song,” they will trigger autobiographical episodic memories.

The “Darling, they are playing our song” phenomenon illustrates a widely recognized feature of musical episodic memories; they appear less vulnerable to decay and easier to access compared to other forms of episodic memory and often survive memory impairment. One explanation for these observations is that at least three properties of musical memories are likely to render them robust according to classical memory theory; they are (1) distinct at encoding, (2) frequently rehearsed, and (3) suitable for retrieval.

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