On average, yes. A calibrated visual simple-reaction study involving 1,469 adults aged 18–65 found that reaction time increased by about 0.55 ms per year of age. A separate very large web-based study, MindCrowd, analysed simple visual reaction data from more than 75,000 adults aged 18–85 and also found age-associated variation in performance.
The change is not perfectly linear for every person, and age is only one factor. Health, motor speed, attention, task complexity, practice and hardware all influence a measured score.
You may see online tables claiming that every 20-year-old should score one exact number and every 50-year-old another. Research does not support that level of precision across all tests.
For example, studies listed in Woods et al. report mean simple visual reaction times ranging from roughly the low 200s to nearly 400 ms depending on the apparatus and procedure. That spread is large enough that copying one study into a universal age chart would be misleading.
Age effects often become more noticeable when the task is more complicated. In a national sample of 3,616 adults aged 32–85, older adults were slower on increasingly complex auditory reaction tasks, particularly when switching and executive control were involved.
A systematic review also found that older adults showed greater trial-to-trial reaction-time variability, with larger age effects in choice reaction than in simple reaction tasks.
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