Tachistoscope
Encyclopedia
A tachistoscope is a device
that displays (usually by projecting) 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. Actual tachistoscopes use a slide
or transparency projector
equipped with the mechanical shutter
system typical of a camera
. 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.
used it during World War II
in the training of fighter pilots to help them identify aircraft silhouettes as friend or foe.
became ubiquitous, tachistoscopes were used extensively in psychological research
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
.
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 are typically still based around slide projectors rather than computer monitors, due to
Machine
A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...
that displays (usually by projecting) an image
Image
An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person.-Characteristics:...
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. Actual tachistoscopes use a slide
Slide projector
A slide projector is an opto-mechanical device to view photographic slides. Slide projectors were common in the 1950s to the 1970s as a form of entertainment; family members and friends would gather to view slide shows...
or transparency projector
Overhead projector
An overhead projector is a variant of slide projector that is used to display images to an audience.-Mechanism:An overhead projector typically consists of a large box containing a very bright lamp and a fan to cool it. On top of the box is a large fresnel lens that collimates the light...
equipped with the mechanical shutter
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene...
system typical of a camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
. 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
Shutter speed
In photography, shutter speed is a common term used to discuss exposure time, the effective length of time a camera's shutter is open....
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 RenshawSamuel Renshaw
Samuel Renshaw was an American psychologist whose work became famous for a short period of time during World War II when he taught soldiers to identify enemy aircraft in a split second, using tachistoscopic training. He generally worked with fast-reading and enhancing the latent ability of the mind...
used it during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
in the training of fighter pilots to help them identify aircraft silhouettes as friend or foe.
Applications
Before computersPersonal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
became ubiquitous, tachistoscopes were used extensively in psychological research
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
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
Visual field
The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments", while 'field of view' "refers to the physical...
.
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 are typically still based around 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.