A tachistoscope is a device that displays an image for a specific amount of time. It can be used to increase recognition speed, to show something too fast to be consciously recognized, or to test which elements of an image are memorable. Projection tachistoscopes use a

slide Slide or Slides may refer to: Places * Slide, California, former name of Fortuna, California Arts, entertainment, and media Music Albums * ''Slide'' (Lisa Germano album), 1998 * ''Slide'' (George Clanton album), 2018 *''Slide'', by Patrick Glees ...

or transparency projector equipped with the mechanical shutter system typical of a

camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ...

. The slide is loaded, the shutter locked open, and focusing and alignment are adjusted, then the shutter is closed. When ready for the test, a shutter speed is selected, and the shutter is tripped normally.

History

The first tachistoscope was originally described by the German physiologist A.W. Volkmann in 1859. Samuel Renshaw used it during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

in the training of fighter pilots to help them identify aircraft silhouettes as friend or foe.

Applications

Before computers became universal, tachistoscopes were used extensively in

psychological research Psychological research refers to research that psychologists conduct for systematic study and for analysis of the experiences and behaviors of individuals or groups. Their research can have educational, occupational and clinical application ...

to present visual stimuli for controlled durations. Some experiments employed pairs of tachistoscopes so that an experimental participant could be given different stimulation in each

visual field The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments". Or simply, visual field can be defined as the entire area that can be seen when an eye is fixed straight at a point ...

. Tachistoscopes were used during the late 1960s in public schools as an aid to increased reading comprehension for

speed reading Speed reading is any of many techniques claiming to improve one's ability to read quickly. Speed-reading methods include chunking and minimizing subvocalization. The many available speed-reading training programs may utilize books, videos, ...

. 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. The second type projected words and phrases on a screen in sequence. Both types were followed up with comprehension and vocabulary testing.Brown, James I
"Teaching Reading With the Tachistoscope"
''Journal of Developmental Reading'', Winter, 1958, 1(2)8–18 Tachistoscopes continue to be used in market research, where they are typically used to compare the visual impact, or memorability of marketing materials or packaging designs. Tachistoscopes used for this purpose still typically employ slide projectors rather than computer monitors, due to * the increased fidelity of the image which can be displayed in this way and * the opportunity to show large or life-size images.

References

{{Reflist * Benschop, R. (1998). "What Is a Tachistoscope? Historical Explorations of an Instrument". ''Science in Context'', 11:23–50.

External links

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