Change Blindness Test — Free Flicker Task: Spot the Changing Shape

Change blindness is the failure to notice even a sizable change in a scene right in front of you when attention is not on that spot. In 1997 Rensink and colleagues used a flicker method — inserting a brief blank between two versions of a picture to erase the motion signal at the moment of change — and showed that people take surprisingly long to find the difference. This test is Soundary's own implementation of that paradigm using scenes of shapes.

Each scene contains 12 to 16 shapes and cycles continuously: original for 0.24 seconds, blank for 0.08, changed scene for 0.24, blank for 0.08. Only one shape changes — its color, whether it is present, or its orientation. Tap the changing shape as soon as you find it; a wrong tap does not end the search. There are 8 scenes, the last 4 with subtler changes, and each allows up to 60 seconds.

Because the blank erases the motion cue, finding the change requires placing attention on one shape after another and comparing each with memory. Detection time is therefore an index of how efficiently you move attention around a scene while checking it against visual memory.

The headline score is the mean detection time in seconds across the scenes where you found the change. The app describes under 6 seconds as very fast, under 15 as typical, under 30 as somewhat slow and 30 or more as long, and separately shows how many scenes you did not solve within 60 seconds. Wrong taps are also listed.

The overall battery score is 0-100, weighting detection rate at 60% and speed at 40%. Speed maps a mean detection time of 5 seconds to full marks and 30 seconds to zero, scaling linearly in between — so finding changes quickly but missing a few scenes costs you on detection rate, while finding them all slowly costs you on speed.

Detection time varies widely because each scene differs in change type and number of shapes, and the mean shifts considerably depending on which of the 8 scenes you missed. It is also common for the first scene to take long on a first attempt while you get used to the format, so look at the trend across repeated measurements rather than a single result.

Change detection requires constant comparison against visual memory, so it is sensitive to fatigue and lack of sleep — after a poor night the same scene takes much longer. Caffeine may slightly speed the search but can add hasty wrong taps, and longer detection times with age are a natural change. A small or dim screen and difficulty distinguishing colors also make color changes harder to spot.

Soundary saves your results and shows the change from your previous test. Repeating every one to two weeks on the same device at a similar brightness and time of day, and following the trend in mean detection time and missed scenes, helps you tell condition-related fluctuation from steady change. This is a self-check, not a diagnostic tool.

If, even after resting well, you repeatedly fail to find several of the 8 scenes within 60 seconds, and in daily life you struggle to notice changes around you or where things have been placed, consider an eye examination together with a professional assessment of attention and visual cognition.