Critical state changes must remain perceptible under reduced motion

What it is

If reduced mode also wipes the traces of a state switch, payment success and payment failure become a silent refresh. Critical states — error, success, permission, unsaved — still have to be seeable after large travel is removed. Perceptibility comes from a marker, copy, colour or a brief fade, not from smuggling travel back in.

Why it happens

Large travel is often treated as the only change channel. Turn it off and, if the implementation has no second channel, the UI falls back to a discrete refresh, and change blindness lands where the cost of missing is highest. Critical states are often off the centre of interest: an error at the bottom of a form, a success on a button already left. Without a transient or a marker, attention will not go looking.

The second channel has to stand on its own: a colour change with enough contrast, text appearing near the original location, a short opacity or border. What they share is small optic flow and a local change in spatial frequency. If that channel exists only when “motion is fully on,” the reduced branch deletes safety-critical visibility.

Studying it

Run change detection for state under reduced conditions: an error appearing, a payment result, a save failure. Compare refresh with no cue, a static marker, and a short fade. Dependent measures: detection rate, time to notice, rate of mistaking the outcome for success. Include a condition where people are not told “an error will occur,” or lab detection will be inflated.

Where it stops holding

• Decorative, non-critical micro-changes may vanish when reduced; not every hover needs a marker.
• Screen-reader users may never see the visual form of the second channel and still need a semantic status announcement; visual perceptibility does not replace that.
• Flashing markers have a photosensitivity ceiling; high-frequency flicker must not compensate for missing travel.

Applying it

• List critical states and, for the reduced branch, specify a non-travel cue per item: copy appearing, colour switch, short fade, icon swap.
• Place the cue at the change or near current focus, not only on a distant badge.
• Check: OS reduced on, no prior warning of failure, walk a failed payment or a validation error. If the outcome cannot be named, the critical change is invisible when reduced.

Related

• Same group: F7.08.1 The OS reduced-motion setting must be honoured · F7.08.2 Reduced is not off; a fade can replace travel
• Nearby: A5.04.3 Changes need motion or a marker to be pointed out · J4.10 Flicker and photosensitivity · R3.09.3 Dynamic changes need a live announcement, not only a style change
• Search terms: reduced motion · change detection · critical state