Overview

• Meta-analysis of 24 studies shows that 1.5× playback speeds reduce comprehension by about 2%, while 2.5× speeds cut recall by up to 17 percentage points.
• Faster audio-visual playback elevates cognitive load beyond working memory capacity, hindering information encoding and storage.
• Adults aged 61 to 94 are significantly more susceptible to retention and recall declines than younger individuals when content is accelerated.
• An estimated 89% of California students surveyed admit to adjusting playback speeds in online courses to save time or maintain focus.
• Specialists recommend moderating speed adjustments for complex material and older learners as the long-term impact of habitual acceleration remains unclear.