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Re: guideline 7.1 about screen flickering (fwd)

From: Anne Pemberton <apembert@erols.com>
Date: Wed, 01 Aug 2001 07:18:31 -0400
Message-Id: <>
To: Marja-Riitta Koivunen <marja@w3.org>, "Jonathan Chetwynd" <j.chetwynd@btinternet.com>, "gregory j. rosmaita" <oedipus@hicom.net>, <w3c-wai-gl@w3.org>
         I didn't ask for "good references from the web" that defined 
anything, I wanted an example of a movement on an actual site that kept 
you, yourself, from understanding what was there. Over the past two years, 
I've watched some 650 kids learn to use the computer and thoroughly enjoyed 
all the movement included in their games and on the web sites I gave them 
to use. So the definition is over-ridden by the observation of actual 
people using computer and the web ...

A further note: If your intent in this line of reasoning is hope that you 
will be able to do away with banner ads on the web, you probably need to 
think this through better. Advertisers aren't lining up waiting to hear our 
words of wisdom.

As for using Jakob Neilsen as a reference is like asking me to read the 
wisdom on a sheet of toilet paper. As I told Kynn yesterday, Neilsen has a 
disclaimer for not including graphics on his site which is so 
overwhelmingly irritating and annoying that I am unable to read anything 
else on his site.


At 04:00 AM 8/1/01 -0400, Marja-Riitta Koivunen wrote:
>I agree we learn to see but many things also develop normally in a certain 
>way e.g. in our visual cortex there are cells specialized in detecting 
>movement and it is hard keep the eye saccades out of the movement if it is 
>strong enough. That is why advertisers want to use movement in the banners 
>as it easily get's the user's attention.
>I tried to find a good reference from the Web, but it was difficult 
>without going too deep and I don't have more time now. The more 
>understandable references are similar to this one:
>In the visual periphery we can instantly detect even slight movement.
>This is an important safety feature, developed long ago to recognize 
>stalking predators. The eye's periphery reports a movement, the brain 
>thinks it's important, and the vision is automatically centered on the 
>threat. It is so imprinted on us that we can't do anything about it, and 
>Also Jacob Nielsen refers to it.
>At 10:51 AM 7/30/2001 -0400, Anne Pemberton wrote:
>>         While your point is well taken, your reason is not based on 
>> fact. A cognitive system is not built and dropped in place, it is 
>> *built* or developed over one's lifespan, and not all cognitive systems 
>> are built to respond the same way to all stimuli whether movement, 
>> sound, or images (including images of text, since for perhaps most web 
>> user, text comes to them as an image).
>>         Most of us trained our cognitive systems before the stimuli 
>> under discussion was invented. Children growing up with this type of 
>> stimuli will learn to respond to it more appropriately than us old geezers do.
>>         Have you tried to read material close to a flickering source? 
>> What site? so we can all test it. Or do you mean to say that you have 
>> tried to read material close to a moving source, an animation, for 
>> example (like that RADAR icon), and you were unable to read the text? 
>> How close was the animation? Was text size appropriate to the icon or 
>> did one overpower the other? What site did you test it on? Were there 
>> any contributing factors preventing your understanding other than the 
>> problem graphic? Does this happen whenever you encounter certain type of 
>> graphics? Is there any reason that hitting the stop button (or the 
>> equivalent in your browser) is insufficient? Does it help to enlarge the 
>> text size near a competing graphic?
>>         An remember, that being irritated or annoyed is not a disability.
>>                                                         Anne
>>At 09:52 AM 7/30/01 -0400, Marja-Riitta Koivunen wrote:
>>>At 06:49 AM 7/27/2001 +0100, Jonathan Chetwynd wrote:
>>>>given that placements are a more subtle way of advertising, perhaps in the
>>>>RADAR case and given the client group, it might make sense to advise 
>>>>that an
>>>>animated gif is liable to irritate, rather than rely on a medical 
>>>And not only to irritate. Sometimes it makes it almost impossible to 
>>>read a text that is near a flickering image as our cognitive system is 
>>>built to pay attention to the movement.
>Anne Pemberton
Received on Wednesday, 1 August 2001 07:40:39 UTC

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