The Effects of Mixed Working Memory Training on Subsequent Training Gains Among Older Adults

Within conventional assessments of transfer that examine the effects of training on measures of function at a single time point, these ideas has not been tested. In this project, a "successive-enrichment" paradigm was used to examine improvement in cognitive skills as a function of different conditions for earlier training. The target for training is working memory (WM) given its centrality in models of attention, intellectual function, and everyday capacities such as reasoning and language comprehension.

In the successive-enrichment paradigm, all participants receive the same target training, but the nature of the training that precedes it is manipulated. Thus, in Phase 2, all participants are trained for 10 days on the reading span task (RdgS), in which the task is to verify sensibility in a set of sentences and retain in memory an alphabetic character presented after each sentence. The set size adapts to the participant's skill (in both accuracy of sensibility decisions and memory for the letter set). In Phase 1, participants are randomly assigned to one of four groups designed to test the assumption that related and diverse experiences with the target skill differentially enhance the rate of learning the new skill. In the Same Task (ST) control, participants train on the RdgS, and were expected to be at ceiling in Phase 2. In the Different Single condition (DS), participants trained on a WM task different from that in Phase 1 (the lexical decision span). In the Different Mixed (DM) condition, participants trained on two different interleaved WM tasks, the lexical decision span and the category span. In the non-WM Placebo Control (PC), participants train on a speeded lexical decision task (matched in materials and verbal decision component to the lexical decision span the but requiring no simultaneous memory.

Outcome measures include pre- to posttest gains in working memory and episodic memory, as well as the rate of gain in learning the RdgS in Phase 2. The PC and ST controls define the lower and upper limits of performance, respectively. The principle of enhanced mutualism would predict that the DM group will show more efficient learning of the RdgS in Phase 2 than the DS group, which will both show more efficient learning than the PC group.