A friend sent us a couple of those graphics that appear to be rotating or undulating even though nothing is actually moving. It’s kind of a cool illusion but they added this bit
I’m a bit suspcicious but I don’t have any elderly child alleged criminals to test this on and Snopes was no help either.
I don’t know how well the apparent movement correlates with stress-coping ability or criminality, but I found it varied with my eye movement.
If I made a concious effort to fix my eyes on one part of each pattern, I could kill the apparent movement more-or-less dead. If I deliberately tracked all over the patterns, I could make the apparent movement more pronounced.
If this is generally true, then I guess we can spot the criminal types by their twitchy eyes! Let’s round them up before they can cause any mischief.
Like matt I found it depended on where I focussed. THe fisrt pattern (flower shapes) as soon as I focussed on one ‘flower’ it stopped moving - but started again as I moved my focus to another one (like playing Grandmother’s footsteps!); the second image rippled gently but again I could ‘stop’ it.
Also I found that there is an optimal distance for vewing, too far back or too close and the ‘movement’ slows until it practically disappears.
For the record I am neither elderly nor a child, crimminally insane or particularly stressed - in fact I’m barely awake and need another mug of tea !
Both of those are variants of a well-known optical effect called the “Peripheral drift illusion.”
The effect has nothing to do with stress. The basic peripheral drift illusion is based on the way that your retinas respond to luminance (brightness.) As the rods at the periphery of your retinas are stimulated, they rapidly become desensitized, so the same stimulus results in an apparant luminance that is less bright. Contrawise, the areas that receive little stimulation rapidly become more sensitive. In effect, as your eyes try to follow the motion, the bright areas are constantly dimming, and dim areas are constantly brightening, and since they are strategically arranged, there is an illusion of motion – the “middle” section, being appears to move from in the direction of the brighter areas. (In the past, this effect has usually been exploited with gradients rather than arrangements of “high/middle/low” patterns, but the theory is the same.)
Both of the examples that you have linked to are ones that have been developed by a professor of psychology at the University of Kyoto named Akiyoshi Kitoaka. He has improved the illusion by introducing a chromatic element to them, so the cones in your retinas play along, too.
A couple of weeks ago, another optical illusion thread here prompted me to fire up Photoshop and knock off a big-assed version of my favourite of Professor Kitoaka’s retinal motion illusions.
Here is a link to the good professor’s webpage, where you can find more examples of this illusion (and many others) and a detailed exposition on the theory behind them.
I’m a pretty stresed person and I’ve been called ‘shifty-eyed.’ My life has been extra stressful lately. The only picture I see moving is Larry Mudd’s “big-assed version of [his] favourite of Professor Kitoaka’s retinal motion illusions.” (That’s really cool!)
IANA senior citizens, nor a kid.
Not a whole lot of motion for me, unless I intentionally look “all over the picture.”
Plenty of stress at my work location today.
The explanation you cited may have come from a mis-remembered or misinterpreted explanation of the phenomenon. The physiological explanation given by Larry Mudd might be summed up as “stress” on the optic system, but it has nothing whatsoever to do with “stress” in our lives as we frequently use this term. It’s like saying that a floor which collapsed because of too much weight (stress on the structural members) was somehow correlated with the emotional health of the people walking on it.
That’s a charitable theory, micco. 
I’m a cynical bastid, myself, and I think I have found the source of the misinformation.
This huckster “hypnotism” site uses mostly-identical wording, and also contains other novelty items that have been around for ages without having any diagnostic uses attributed to them.
The site has an “information purposes only” disclaimer, which is a weak way of trying to avoid liability for fraud.
The “stress test” is expected to appear to move, which might lead a credulous person to accept that they have been diagnosed as having problems with stress. Why would they want to fake someone into thinking they’re stressed?
Because they’re selling hypnomagical stress-reduction CDs, of course.
The .gif files on their site are lifted directly from Kitoaka’s site(not even resized or recompressed) and in spite of Kitoaka’s prominent TOS disallowing use of his illusions on commercial sites or without attribution, the Stage Hypnotist at a Car Boot Sale claims all content as the “intellectual property of Mind Motivations and Rick Collingwood.”
What a douchebag.
I think I know why old people don’t see them move.
I can stop ALL movement on the flower one by unfocusing my eyes very slightly. How many old people do you know with perfect vision eh? eh? 
Heh. This week’s image challenge over at b3ta is “Using hypnotism for evil.” I made up a quick-and-dirty exploit of this effect for my entry.
Working link. Compo entries are trickier to link to. :o
