Why do we blink so much?

The obvious function is maintenance: blinking spreads tear film across the cornea, clears debris, and delivers oxygen and nutrients to a surface with no blood supply of its own. But the frequency is the puzzle. Adults blink roughly 15 to 20 times a minute, which is several times more often than lubrication alone appears to require, and adds up to a significant portion of waking time spent with the eyes closed, without any perceived interruption in vision because the brain suppresses awareness of the gap.

Research using brain imaging found that spontaneous blinks briefly activate the default mode network, associated with internal thought and rest, suggesting blinks provide momentary attentional breaks. Supporting this, studies show blinks are not randomly distributed: people watching video blink at predictable implicit breakpoints, at the end of a sentence or when a scene's action pauses, and audiences watching the same film tend to blink in synchrony at those moments, which implies the brain schedules blinks for when the least information will be lost. Blink rate also varies meaningfully with mental state, dropping sharply during concentrated visual tasks, which is precisely why screen work causes dry eye, and rising with anxiety and certain neurological conditions, making blink rate a research measure in Parkinson's and schizophrenia.