Re: Invisible werewolves in 3D

[P3D John W Roberts <roberts@xxxxxxxxxxxxxxxxx>]

>Date: Sat, 23 Aug 1997 22:12:25 -0500
>From: "P3D Dr. George A. Themelis" <fj834@xxxxxxxxxxxxxxxxxxxxx>

>[Note: I had to change the subject line because I am sure no one
>is reading the "Driving and 3d" thread any more... :-) :-) :-)]

Ditto.

>John Roberts writes:

>>Your line of reasoning appears to include a strong implicit assumption
>>that quality of visual information for a driver is judged by a Boolean
>>criterion - that either "there is sufficient visual information for
>>driving" or "there is not sufficient visual information for driving".

>I am sure that Driving License authorities use similar "Boolean
>logic" to decide whether they will issue a driving license or not.
>They have to draw the line somewhere...

Well, Sometimes restrictions are noted - usually things like a requirement
to wear glasses, but also driving conditions, such as "Limited to daylight
only". (That's one of the options listed on the Maryland driver's license -
14 restriction codes are listed, including "Limited (See Special Restriction
Card)", so I don't know how sophisticated they get in their restriction
codes. For a regular automobile driver's license, Maryland tests for vision
with each eye, both eyes working together, and peripheral vision, but not
for stereo vision.

>For me the argument is not if there is sufficient information or not
>but whether the stereopsis information is important or not, or, 
>better, how important is it?  I tend to believe that, during driving, 
>it is not very important, based on the fact that most objects that 
>demand our attention in our visual field (cars, etc.) are far away and 
>in constant motion.

I consider stereoscopic vision to be useful out to at least 100 feet.
Also motion tends to be mostly toward or away from the observer -
not optimum for judgement of distance, and cars going the same way may
have little or no relative motion most of the time. I'm not saying that
stereo vision is required to drive a car, but that when I am deprived of it,
my brain has to work harder to try to compensate for the lost information,
and may be reallocating processing power that would be better used for some
other aspect of the driving.

>And I do not disagree with you.  I am sure it will be missed, especially
>if that person had it, used it, and lost it.  But is it missed for a 
>person who was born without it?  

An interesting question - I don't know the answer. As Jim C mentioned, it
may be hard to think of a way to test this that does not introduce some
sort of bias into the results from other disabilities, percentage of a group
who are licensed drivers, etc.

John R


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