Autobiographical knowledge base The autobiographical knowledge base contains knowledge of the self, used to provide information on what the self is, what the self was, and what the self can be.[3] This information is categorized into three broad areas: lifetime periods, general events, and event-specific knowledge.[2]

Lifetime periods are composed of general knowledge about a distinguishable and themed time in an individual's life, such as the period you spend at university (university theme), or when you entered the workforce (work theme). Lifetime periods have a distinctive beginning and ending, but they are often fuzzy and overlap.[2] Lifetime periods contain thematic knowledge about the features of that period, such as the activities, relationships, and locations involved, as well as temporal knowledge about the duration of the period.[2] The thematic information in these periods can be used to group them together under broader themes, which can reflect personal attitudes or goals.[2] As an example, a lifetime period with the theme of “when I lost my job” could fall under the broader category of either “when everything went downhill for me" or "minor setbacks in my life."

General events are more specific than lifetime periods and encompass single representations of repeated events or a sequence of related events.[2] General events group into clusters with a common theme, so that when one memory of a general event is recalled, it cues the recall of other related events in memory. These clusters of memories often form around the theme of either achieving or failing to achieve personal goals.[2] Clusters of general events that fall under the category of “first-time” achievements or occasions seem to have a particular vividness, such as the first time kissing a romantic partner, or the first time going to a ball game.[4] These memories of goal-attainment pass on important information about the self, such as how easily a skill can be acquired, or an individual's success and failure rates for certain tasks.[2]

Event-specific knowledge (ESK) is vividly detailed information about individual events, often in the form of visual images and sensory-perceptual features.[2] The high levels of detail in ESK fade very quickly, though certain memories for specific events tend to endure longer.[5] Originating events (events that mark the beginning of a path towards long-term goals), turning points (events that re-direct plans from original goals), anchoring events (events that affirm an individuals beliefs and goals) and analogous events (past events that direct behaviour in the present) are all event specific memories that will resist memory decay.[5]

The sensory-perceptual details held in ESK, though short-lived, are a key component in distinguishing memory for experienced events from imagined events.[6] In the majority of cases, it is found that the more ESK a memory contains, the more likely the recalled event has actually been experienced.[6] Unlike lifetime periods and general events, ESK are not organized in their grouping or recall. Instead, they tend to simply 'pop' into the mind.[2] ESK is also thought to be a summary of the content of episodic memories, which are contained in a separate memory system from the autobiographical knowledge base.[3] This way of thinking could explain the rapid loss of event-specific detail, as the links between episodic memory and the autobiographical knowledge base are likewise quickly lost.[3]

Alt text

Hierarchical structure of the autobiographical knowledge base
These three areas are organised in a hierarchy within the autobiographical knowledge base and together make up the overall life story of an individual.[3] Knowledge stored in lifetime periods contain cues for general events, and knowledge at the level of general events calls upon event-specific knowledge.[2] When a cue evenly activates the autobiographical knowledge base hierarchy, all levels of knowledge become available and an autobiographical memory is formed.[2]