atw: Re: Tell the U.S. Marines to Getz Tuft


Brine:

At Wednesday, 24/10/2007, 08:28 PM;, you wrote:
standard multiplication of [raw reading speed] times
[tested time-delayed comprehension] to arrive at the
corrected reading speed

Miles Tinker (show the man some respect, Brean) shone a light spot on the subject's eyes at an oblique angle and tracked its reflection.  Yes, even in 1962 scientists had steam-powered apparatus constructed of the finest British cardboard that enabled them to conduct this sort of measurement. 

As you may or may not know, our eyes constantly saccade, that is, flick in minute steps about the visual field.**  When you are reading, your eyes flick across the line of type from left to right.  Tinker measured the number of saccades required to sweep each line and also the number of retraces, where the subject looked back at words already read.  He also measured the total time to read the test passage -- easily obtained when the subject dropped their eyes to the special target at the foot of the page.

Subjects then had to answer comprehension questions immediately after each test in order to check comprehension (and not memory).  He also asked subjects to rank passages according to their preferences for perceived legibility.  Throughout the book he consistently gives preferences and the corresponding measure.  He also applied a number of other objective measures promoted by various researchers in legibility but found them to have little correlation with each other, the comprehension tests, or his own saccade measurements.

It is interesting that subjects rated Kabel Light so lowly subjectively when his tests showed that most of the time it performed quite well.  It seems to indicate that readers are biased towards typefaces with which they are familiar.  If only Agfa Monotype, Mergenthaler, Microsoft, etc. would fund a replication of Tinker's study using the more sophisticated instrumentation available today, including sans-serif as well as serif and decorative faces, both in print on different coloured papers under varied lighting conditions, and on screen.  Dream on ...

So, Briany, before you criticise a study about which you clearly know nothing, I suggest you nip along to your nearest graphic arts college and read Tinker's study thoroughly.  It matters not a whit what Cambell and Stanley say unless you can specifically apply their findings to Tinker's study.  As far as I know, this is the only thorough objective study of legibilty around and, over 40 years later, we still don't have any follow up.  Colin Wheildon's research is also valuable but more particularly for questions of layout than legibility of type.  His study is also hampered because it is based entirely on subject's preferences and not on objective instrumentation, and is therefore biassed by the subject's familiarity with current practice.

Regards,
Hedley

** A recent fascinating article on human perception in a recent New Scientist shows how you can demonstrate to yourself that, during a saccade, the brain's visual processing switches off and you are blind. Then, when your eyes come to rest, the brain processes visual information again and you are sighted.  So when the motorist pleads in court that he really didn't see the little dog, it could well have been that the dog darted onto the road during a saccade.


--
Hedley Stewart Finger
28 Regent Street   Camberwell VIC 3124   Australia
Tel. +61 3 9809 1229   Mobile +61 412 461 558,
E-mail < mailto:hfinger@xxxxxxxxxxxxxxxxxx>
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