The Effects of Mixed Working Memory Training on Subsequent Training Gains Among Older Adults
Condition: Cognitive Aging
Study type: Interventional

Summary: 
      While an intellectually active and socially integrated lifestyle shows promise for promoting
      cognitive resilience, the mechanisms underlying any such effects are not well understood. The
      aim of the current project is test the implications of the "mutualism" hypothesis, which
      suggests that intellectual function emerges out of the reciprocal influence of growth in
      abilities as they are exercised in the ecology of everyday life. Such a view implies that
      improvement in one component will enhance the modifiability of a related component. An
      additional aim was to test the idea that mutualistic effects will be enhanced by more diverse
      training in related skills, such as interleaved training of multiple skills, relative to
      single-component training.

      A "successive-enrichment" paradigm was developed to test this with working memory (WM) as the
      target for training given its centrality in models of attention, intellectual function, and
      everyday capacities such as reasoning and language comprehension. All participants receive
      the same target training, but the nature of the training that precedes it is manipulated.
      Outcome measures include pre- to posttest gains in working memory and episodic memory, as
      well as the rate of gain in learning the target task. The principle of enhanced mutualism
      would predict that more diverse experiences related to the target skill will enhance
      efficiency in acquiring the target skill.
    

Detailed description: 
      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.
    

Intervention name(s): Different Mixed Condition (DM); Different Single Condition (DS); Same Task (ST) Practice Control; Non-WM Placebo Control (PC)
Intervention type(s): Behavioral; Behavioral; Behavioral; Behavioral
Intervention description(s): Participants engage in home-based training on two working memory tasks, both different from those in the target task training. Goal is 10 days of training, with 4 8-min blocks of training each day.; Participants engage in home-based training on a working memory task that is different from that in the target task training. Goal is 10 days of training, with 4 8-min blocks of training each day.; Participants engage in home-based training on the exact same working memory tasks as that in the target task training. Goal is 10 days of training, with 4 8-min blocks of training each day.; Participants engage in home-based training on speeded verbal decision, which unlike the target task training, has no memory component. Goal is 10 days of training, with 4 8-min blocks of training each day.
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: Single (Participant)
Primary purpose: Basic Science