of this exercise is to find out how much the speed of human word and
number perception varies, and how that affects reading comfort and
choice of career. Specifically -
how long does
the image of a number or a word have to be displayed, in order for
you to see it clearly,
and how much
time gap do you need between images for you to see them clearly?
This visual persistance tester was originally created as part of an on-line survey MA research project, to collect
global data about the relationship between visual persistence duration
(VP) (see below) and reading speed.
The research questions
What is the
distribution of VP in the human population?
Is VP duration
correlated with reading speed, difficulty, first written language
Is VP duration
correlated with choice of work / profession?
Is VP duration
effected by colour contrasts?
is a feature of our perceptual system. Visual images (letters of the
alphabet for example), persists in our visual system for around 40
- 300 milliseconds after the stimulus is removed from view. Some people
have a fast image decay time and others hold images for longer. When
we are presented with a rapid sequence of images (such as when reading
or tracking movement) a backlog of persisting images can build up,
resulting in multiple images persisting simultaneously. The brain
reacts by paying more attention to some of the conflicting images
and ignoring or delaying the perception of others.
(one image being prioritized over another) is often called 'masking'
in the literature and may result in a range of perceptual distortions
and deletions - letters appearing to move about or change position,
reversals, parts of words or letters missing, etc. We (Snakes and
Ladders Charitable Trust) have found that all our 'dyslexic' students
have a VP speed near the longer end of this natural range, (and read
relatively slowly) and that all our teaching staff have VP speeds
near the shorter end of the range, and can read very fast. This raises
the question of whether people's choice of occupation may be effected
by their visual persistence.
If you can spare
a few minutes to take part in this anonymous survey - this is what
we would like you to do.
Click either of
the 'START. . . ' buttons at the top of the page. This displays a
sequence of either numbers or words. You can control the speed of
the displays by clicking on the two rows of radio buttons above the
display - these control the time delays in milliseconds (ms). The
second row controls the duration of each image display. The
top row controls the time gap between each image display. You
can stop the display at any time with the 'Stop Displays' button.
You can then restart either display.
Please take a note of the shortest gap duration
in ms at which you are perfectly comfortable
reading the words and numbers - at each of the three image duration
speeds. Please try to resist the temptation to report that you can
read the images faster than you actually can :-)
The displays use
a range of different foreground and background colours. Please notice if any of these colour combinations are particularly
good or bad for your visual system.
There was originally a report form collecting results in an anonymous database. This is no longer active.