Memorizing while walking: increase in dual-task costs from young adulthood to old age.

The dual task of memorizing word lists while walking was predicted to become more difficult with age because balance and gait are in greater need of "attentional resources." Forty-seven young (ages 20-30 years), 45 middle-aged (40-50), and 48 old (60-70) adults were trained to criterion in a mnemonic technique and instructed to walk quickly and accurately on 2 narrow tracks of different path complexity. Then. participants encoded the word lists while sitting, standing, or walking on either track; likewise, speed and accuracy of walking performance were assessed with and without concurrent memory encoding. Dual-task costs increased with age in both domains; relative to young adults, the effect size of the overall increase was 0.98 standard deviation units for middle-aged and 1.47 standard deviation units for old adults. It is argued that sensory and motor aspects of behavior are increasingly in need of cognitive control with advancing age.