Tachistoscope

A tachistoscope is a device that displays a picture, text, or an object for a specific amount of time.

It can be used for various purposes such as to increase recognition speed, to show something too fast to be consciously recognized, or to test which elements of a display are memorable.

[2] Samuel Renshaw used it during World War II in the training of fighter pilots to help them identify aircraft silhouettes as friend or foe.

[3] Before computers became universal, tachistoscopes were used extensively in psychological research to present visual stimuli for controlled durations.

There were two types: the student would look through a lens similar to an aircraft bombsight viewfinder and read letters, words, and phrases using manually advanced slide film.