A tachistoscope is {a device used historically in experimental Cognitive science to present a stimulus for a brief period}.
After the stimulus is briefly presented, it’s often followed by {a mask} (e.g. {a random pattern of related forms, like jumbled letters for a word stimulus}), intended to {interrupt further processing of the original stimulus}.
Q. What do cognitive scientists call very brief displays of stimuli in their experiments?
A. tachistoscopic presentations
One key application is in studies of recognition in Human perception: can objects be recognized when presented for just 20ms?