The ACTIVE (Advanced Cognitive Training for Independent and Vital Elderly) study is a large-scale, randomized, controlled trial designed to evaluate the effectiveness of cognitive training interventions on mental abilities and daily functioning in older, independent-living adults. The study involved 2832 participants aged 65 to 94 years recruited from senior housing, community centers, and hospital/clinics in six metropolitan areas in the United States. Participants were randomly assigned to one of four groups: memory training, reasoning training, speed-of-processing training, or a no-contact control group. Each intervention group received a 10-session training program, and a 4-session booster training was offered to a random sample of participants in the treatment groups. The primary outcomes measured cognitive function and cognitively demanding everyday functioning. The results showed that all three interventions improved the targeted cognitive abilities compared to baseline, with effects lasting up to 2 years. Eighty-seven percent of speed-trained, 74% of reasoning-trained, and 26% of memory-trained participants demonstrated reliable cognitive improvement immediately after the intervention period. Booster training enhanced the gains in speed and reasoning interventions, which were maintained at the 2-year follow-up. However, no significant effects on everyday functioning were detected at 2 years. The study concluded that cognitive training interventions effectively improved targeted cognitive abilities, with effects equivalent to the expected decline in elderly persons without dementia over 7 to 14 years. However, due to minimal functional decline across all groups, longer follow-up is needed to observe training effects on everyday function. The ACTIVE study is the largest trial to date of cognitive interventions for improving specific cognitive and perceptual abilities in older adults.The ACTIVE (Advanced Cognitive Training for Independent and Vital Elderly) study is a large-scale, randomized, controlled trial designed to evaluate the effectiveness of cognitive training interventions on mental abilities and daily functioning in older, independent-living adults. The study involved 2832 participants aged 65 to 94 years recruited from senior housing, community centers, and hospital/clinics in six metropolitan areas in the United States. Participants were randomly assigned to one of four groups: memory training, reasoning training, speed-of-processing training, or a no-contact control group. Each intervention group received a 10-session training program, and a 4-session booster training was offered to a random sample of participants in the treatment groups. The primary outcomes measured cognitive function and cognitively demanding everyday functioning. The results showed that all three interventions improved the targeted cognitive abilities compared to baseline, with effects lasting up to 2 years. Eighty-seven percent of speed-trained, 74% of reasoning-trained, and 26% of memory-trained participants demonstrated reliable cognitive improvement immediately after the intervention period. Booster training enhanced the gains in speed and reasoning interventions, which were maintained at the 2-year follow-up. However, no significant effects on everyday functioning were detected at 2 years. The study concluded that cognitive training interventions effectively improved targeted cognitive abilities, with effects equivalent to the expected decline in elderly persons without dementia over 7 to 14 years. However, due to minimal functional decline across all groups, longer follow-up is needed to observe training effects on everyday function. The ACTIVE study is the largest trial to date of cognitive interventions for improving specific cognitive and perceptual abilities in older adults.