[playful page] A toy, not a test. It runs in your browser; nothing you do here is sent anywhere, and the only thing kept is a "played" tick in your own browser so the toy shelf can show it.

TOY #3 OF 6 works with a mouse, a finger or a keyboard

wo pictures take turns, with a pale blank screen between them. One thing differs between the pictures: a colour, a shape, or something missing. Click or tap it when you find it. Three rounds, then one round without the blank.

About the flicker: the pictures change about once every 0.7 seconds, the blank is a pale lilac rather than black, and the box is small. If your device asks for reduced motion, nothing moves on its own; you step through the pictures with a button.

This toy needs JavaScript. The notes below still say what it would have shown.

What it shows. Change blindness. Rensink, O'Regan and Clark showed people two versions of a photograph alternating with a brief blank between them; large changes often took many alternations to find, and went much faster once attention was drawn to the right place (Rensink, O'Regan & Clark, 1997) [paraphrase, not a quotation]. The blank hides the flicker that a change would otherwise make, so you have to find it by attending to things one at a time. Simons and Levin reviewed the wider phenomenon, including changes people miss in real life (Simons & Levin, 1997) [paraphrase, not a quotation], and Simons and Rensink looked back at what it does and does not say about how much of a scene we keep (Simons & Rensink, 2005). What it cannot show. Twelve coloured shapes are far simpler than a photograph of a street, and the change here can land anywhere, including somewhere you would never look in a real scene. Your times include moving the mouse and deciding to click. Three rounds tell you very little about yourself. Not noticing a change does not prove you stored nothing about it; that is one of the points the later review makes.

Sources

1. Rensink, O'Regan & Clark (1997). To See or not to See: The Need for Attention to Perceive Changes in Scenes. Psychological Science. doi:10.1111/j.1467-9280.1997.tb00427.x
2. Simons & Levin (1997). Change blindness. Trends in Cognitive Sciences. doi:10.1016/S1364-6613(97)01080-2
3. Simons & Rensink (2005). Change blindness: past, present, and future. Trends in Cognitive Sciences. doi:10.1016/j.tics.2004.11.006

see also

	signal detection — seeing something, and saying so, are different steps
	automation bias — missing what nobody flagged
	change blindness — in the glossary