The Generalizability of Dual N-Back Training in Younger Adults

Abstract

Introduction: The popularity of cognitive training has increased in recent years. Accumulating evidence shows that training can sometimes improve trained and non-trained cognitive functions, and these improvements may be related to individual differences in initial capacity and performance on the training task. The current study assessed the effectiveness of a custom-designed n-back task (the N-IGMA) versus an active control task (Blockmaster) at improving various forms of working memory capacity, attention, and fluid intelligence. Three measures of working memory capacity were considered: verbal, visuospatial and observed action. Methods: Outcome measures were assessed pre- and post-training. Nineteen healthy young adults (19-30 years of age) trained at-home for 30 minutes per day, five days a week for three weeks with either the N-IGMA (n=9) or Blockmaster n=10) at-home games. Results: Pre-post changes were observed for some outcome measures and these were equal for the N-IGMA and active control group. Outcome improvements could be due to simple test/re-test benefits or alternatively the N-IGMA and Blockmaster tasks may produce equivalent training effects. Improvements in the training tasks did not correlate with the changes in the outcome measures, suggesting improvements in the outcome measures might not be attributable to transfer of learning. For verbal working memory only, participants with higher (versus lower) initial fluid intelligence demonstrated larger improvements on the outcome measures suggesting that in future research training tasks might need to be tailored to the individual participant. Pre-assessment but not change scores were related for observed action and visuospatial working memory, consistent with some overlap between content domains. Conclusion: Despite specifically targeting working memory, the N-IGMA was not better than a visuospatial control game at improving a variety of cognitive outcome measures in this small sample. Results suggest that the individual’s initial cognitive capacity might need to be considered in future training studies. Caution should be used in extrapolating the results of this study to other populations of interest (e.g., older adults or individuals with cognitive deficits) since the present investigation included relatively high functioning individuals.