Transfer Effects in Task-Set Cost and Dual-Task Cost After Dual-Task Training in Older and Younger Adults: Further Evidence for Cognitive Plasticity in Attentional Control in Late Adulthood

Abstract

Older adults' difficulties in performing two tasks concurrently have been well documented (Kramer & Madden, 2008). It has been observed that the age-related differences in dual-task performance are larger when the two tasks require similar motor responses (2001) and that in some conditions older adults also show greater susceptibility than younger adults to input interference (Hein & Schubert, 2004). The authors recently observed that even when the two tasks require motor responses, both older and younger adults can learn to perform a visual discrimination task and an auditory discrimination task faster and more accurately (Bherer et al., 2005). In the present study, the authors extended this finding to a dual-task condition that involves two visual tasks requiring two motor responses. Older and younger adults completed a dual-task training program in which continuous individualized adaptive feedback was provided to enhance performance. The results indicate that, even with similar motor responses and two visual stimuli, both older and younger adults showed substantial gains in performance after training and that the improvement generalized to new task combinations involving new stimuli. These results suggest that dual-task skills can be substantially improved in older adults and that cognitive plasticity in attentional control is still possible in old age.

This research was supported by a postdoctoral fellowship from the Canadian Institute of Health Research to Louis Bherer and grants from the National Institute on Aging (R01 AG25032 and AG25667) and the Institute for the Study of Aging to Arthur F. Kramer.

Notes

Note. Scores represent number of correct answers, number of correct sequence (span tests), and time to complete the tasks (in seconds).

Note. Experimental sections include pre-test, post-test, and five training sessions.

¹Score for computation span is missing for one participant of the group of younger adults.

²Age-related differences in general slowing are well documented in cognitive aging studies (2001). In the present study, age-related slowing was controlled for by conducting ANCOVAs with baseline RT in the single pure trials averaged for the two tasks performed alone in the first training session used as covariate. In pre- and post-test analyses, baseline RT was averaged separately for each of the four-task combinations (training, within-modality, and cross-modalities 1 and 2) at pretest. In this study, an interaction involving the age group factor is considered significant only if it was also significant in the ANCOVA.

^#To control for general slowing, ANCOVAs were performed using mean RT in single-pure trials at pretest in each of the task combinations as covariate. For each interaction involving the Age group factor.

∗Indicates that the interaction remained significant at .05 level after adjustment for general slowing.

∗∗The effect remained significant at .01 level after adjustment for general slowing.