Disproportionate dual task costs for episodic but not semantic memory retrieval

There has been disagreement in the literature as to whether older adults have a disproportionate deficit in dual tasking. This research examines both task difficulty and domain as possible moderator variables of dual task cost in older adults. In an earlier experiment, 36 older adults and 36 younger adults retrieved either previously learned word paired-associates (episodic retrieval) or overlearned category members (semantic retrieval) under no working memory load and with a working memory load condition. The proportional cost of dual tasking was age-invariant for semantic memory retrieval but was particularly marked for episodic memory retrieval. The data did not support an account based on task difficulty and suggests the age effect in dual task studies is domain specific. To investigate the episodic/semantic distinction further, younger and older adults' performance was examined using another set of episodic and semantic tasks again under conditions of load. The results of both of these experiments will support the argument that dual tasking involving episodic memory retrieval is problematic in older adults.