Does working memory decline with age?
The short answer
Yes — working memory capacity peaks in the mid-20s and declines gradually across the lifespan. By age 70, the average digit span is approximately 5–6 digits vs. 7–8 in young adults. This is one of the earliest and most consistent signs of cognitive aging.
The data
| Age group | Avg digit span | Change |
|---|---|---|
| 18–24 | 7.5 | Peak |
| 25–34 | 7.2 | −0.3 |
| 35–44 | 7.0 | −0.5 from peak |
| 45–54 | 6.6 | −0.9 |
| 55–64 | 6.2 | −1.3 |
| 65–74 | 5.7 | −1.8 |
| 75+ | 5.2 | −2.3 |
What it means for you
The mechanism is primarily a reduction in the speed of neural processing (slower rehearsal in the phonological loop) and reduced efficiency of attention control in the prefrontal cortex. The good news: aerobic exercise is the most effective intervention, with regular exercisers showing working memory performance 10–15 years younger than sedentary peers of the same age.
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Quick Answer
Yes - working memory capacity peaks in the mid-20s and declines gradually. By age 70 the average digit span is ~5–6 vs ~7–8 in young adults. Exercise and cognitive engagement slow this decline.
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