The effect of several mental tasks on the spontaneous eye blink rate in 36 normals was examined. The blink rate during silence was 19.0 blinks/minute. This was significantly lower than the mean blink rate during speech (24.7 blinks/minute) and while listening to a paragraph to be memorized (27.6 blinks/minute). Reading reduced the blink rate to 12.3 blinks/minute. Men were more able to suppress and speed up blinking than women.