The locus of the benefits of repetition-lag memory training

ABSTRACT

The repetition-lag training procedure developed by Jennings and Jacoby (2003, Neuropsychological Rehabilitation, 14, 417) has been shown to improve older adults' performance in the recognition memory task used for training, and to improve performance in a variety of other memory and executive function tasks (Jennings, Webster, Kleykamp, & Dagenbach, 2005, Aging, Neuropsychology, and Cognition, 12, 278). The present study examined the effects of concurrent interference tasks during the study or test phases of training to localize the source of gains. Overall, the results suggest that training is resilient and resistant to interference, but also that the processes used during the test phases of training are more important to the gains seen in the primary task and in the transfer tasks than those used in the study phases.

Keywords:

• Aging
• Memory
• Recognition
• Repetition-lag
• Intervention

Notes

¹There is some controversy over how to calculate effect sizes in repeated measures designs. We are following a convention in the present paper by using a between subjects estimate. However, because this ignores the correlation between pre- and post-training scores, it results in occasional discrepancies between the effect sizes reported and the significance test results. For example, the normal training group improved significantly on the Digit Symbol Substitution Test with a between subjects effect size of 0.31, but only marginally on the AX-CPT with a between subjects effect size of 0.62. If effect size is calculated using a within subjects formula that corrects for the magnitude of the correlation between means, the effect size for the Digit Symbol Substitution Test is 0.78 and the effect size for the AX-CPT is 0.49. In this experiment, the pre and post-training Digit Symbol Substitution Test scores were highly correlated, whereas the AX-CPT task scores were not.