What is change blindness?
Change blindness is failing to notice a change that is in plain sight. When a change happens during a blink, a cut in a film or any brief interruption, people often miss it, even when it is large and they are looking straight at the scene. We feel as if we see everything in front of us, but we only notice a change in the parts we are paying attention to at that moment.
How this test works
Each round shows a picture of 14 colored shapes. Then the picture is replaced by a blank for a moment, then by a copy with one thing changed, then a blank, then the original again, over and over: 240 ms for each picture and 80 ms for each blank. The change is either a color, a shape, or a shape that disappears. Tap the shape that changes. If you haven't found it after 30 seconds, it is circled and the next round begins. There are 8 rounds, with the three kinds of change mixed in about equal numbers.
How is your result calculated?
Your result is how many changes you found, out of 8. Each find is timed from the animation frame that first draws the picture to the moment your finger or mouse button goes down on the right shape, and you see your average and fastest find. A tap on any other shape is counted as a wrong tap and the round carries on.
Why is the change so hard to see?
Without the blank, the change would be easy: a shape changing color would flash, and that flash pulls your eyes straight to it. The blank removes the flash, because everything on screen changes at once, twice a cycle. With no flash to guide you, the only way to find the change is to look at the shapes one by one and compare them across the blink, and that takes attention.
This "flicker" method was introduced by Ronald Rensink, Kevin O'Regan and James Clark in 1997, in the journal Psychological Science. Change blindness also happens in real life: in a 1998 study by Daniel Simons and Daniel Levin, many people giving directions to a stranger didn't notice when the stranger was swapped for a different person while a door was carried between them.
Change blindness vs inattentional blindness
Both are failures to see something in plain sight, in different situations. Change blindness is missing a change between two views of a scene, as in this test. Inattentional blindness is missing an unexpected object altogether while your attention is on something else. In Daniel Simons and Christopher Chabris's 1999 study, about half of the people counting basketball passes in a video didn't notice a person in a gorilla suit walking through the game.
How to find changes faster
- Search systematically. Work through the picture a region at a time instead of looking at the whole thing and waiting for the change to jump out.
- Watch one or two shapes at a time. Comparing a small number of shapes across the blink is easier than trying to hold the whole picture in mind.
- Remember the gaps. A shape that disappears leaves an empty space every other picture. Gaps are harder to notice than shapes.
What can change your result
- Color vision. About a third of the changes are a change of color. If some of the colors look alike to you, those rounds will be harder.
- Screen size. A larger picture spreads the shapes over more of your view, which can make searching slower.
- Luck. If you happen to look at the changing shape first, a round is quick. That is why the test has 8 rounds.
This is a game about how attention works, not an assessment of eyesight or attention. For another search task, try the Visual Search Test, or test what you can hold in mind with the Visual Memory Test.