I think this is a reference to peripheral vision's increased sensitivity
to movement.
I don't agree; movement ≠flicker.
I think the idea behind most of these products (flickering motorcycle
headlights, etc.) is to take advantage of this effect. I'm not sure how
much real science some of these manufacturers have done (selecting the
correct rate and duty cycle) to justify their claims.
You're more charitable (or at least more diplomatic) than I am; I'll
come right out and say it: Most of this homebrew nonsense — flashing
CHMSLs, blinking amber "deceleration lights", motorcycle "headlamp
modulators" and the like — are all marketeering with zero science
behind them. Unfortunately, regulation of vehicular safety equipment in
North America is often more about politics (who shouts the loudest)
than about actual safety performance. So, we get public transit systems
installing "deceleration lights" on their buses without a shred of
evidence they help anything. We get the same motorcyclist foundations
that baselessly parrot stupidities like "Loud pipes save lives!"
lobbying for -- and getting -- permission to flash their headlamps with
"modulators" all day and all night. We get completely unregulated
aftermarketeers selling kits to make your car's CHMSL flash. All with
plenty of hype and commonsensical-sounding but thoroughly unscientific
babble about why each of these is the next great safety breakthrough.
DS