Blinking is related to certain cognitive processes. For example, individuals "punctuate" their speech by blinking between phrases and at the end of sentences. Daydreaming is associated with low rates of blinking. Blinking occurs between fixations and may be timed so as not to interfere with significant visual input. Apparently, blinking occurs at transitions between internal events and is inhibited at other times. In the experiment reported here, blinking was measured while the activity of operational memory was manipulated with mental load kept constant. The rate of blinking was significantly reduced when the cognitive operation of internal counting was being performed. It is inferred that the blink rate is low when information in memory is being operated on. To suspend blinking during certain cognitive activities would be adaptive if blinking disrupts them. Since the blackout period of the blink produces a rapid change in visual level, blinking disrupts those cognitive processes utilizing display areas accessible to visual input. Operational memory and the visual imagination may share components with the visual perceptual system. To protect these vulnerable processes from interference, blinking may be inhibited when they are active.