Episodic and semantic content of memory and imagination: A multilevel analysis.

Autobiographical memories of past events and imaginations of future scenarios comprise both episodic and semantic content. Correlating the amount of "internal" (episodic) and "external" (semantic) details generated when describing autobiographical events can illuminate the relationship between the processes supporting these constructs. Yet previous studies performing such correlations were limited by aggregating data across all events generated by an individual, potentially obscuring the underlying relationship within the events themselves. In the current article, we reanalyzed datasets from eight studies using a multilevel approach, allowing us to explore the relationship between internal and external details within events. We also examined whether this relationship changes with healthy aging. Our reanalyses demonstrated a largely negative relationship between the internal and external details produced when describing autobiographical memories and future imaginations. This negative relationship was stronger and more consistent for older adults and was evident both in direct and indirect measures of semantic content. Moreover, this relationship appears to be specific to episodic tasks, as no relationship was observed for a nonepisodic picture description task. This negative association suggests that people do not generate semantic information indiscriminately, but do so in a compensatory manner, to embellish episodically impoverished events. Our reanalysis further lends support for dissociable processes underpinning episodic and semantic information generation when remembering and imagining autobiographical events.