Trigger the flicker that swaps between two near-identical scenes, then click every shape that quietly changed, before your attention runs dry.
Each level shows a grid of shapes. Press Flicker to blank the screen and switch to the altered scene; a few cells have changed colour, shape or rotation across the blink. Click each changed cell to mark it. Finding them all clears the level and the next gets busier. A gaze budget drains while you study a scene, and exhausting it too many times ends the run.
Spot the Shift is a spot-the-difference puzzle that weaponises the flicker effect, training visual attention against change blindness.
Blanking the screen between two versions of a scene so that changes go unnoticed is the flicker paradigm, the standard laboratory demonstration of change blindness — observers routinely miss major differences introduced while an image flickers off and on.
The original addition is a gaze budget that drains while you study a scene.
That makes the phenomenon's cause into the mechanic. Change blindness is argued to reflect a real limit on attention: without the motion cue a blink removes, you can only compare what you have actually encoded. Charging for looking forces you to choose what to encode, which is the decision your visual system is making anyway.
Spot the Shift is an original free browser spot-the-difference puzzle that weaponises the flicker effect from change-blindness research. Built in-house for PlayPendium.