Change Blindness Test: Spot the Hidden Change

The 24 original puzzles cover color changes, added or removed objects, position shifts, orientation changes, count changes, and small shape details. Desk, street, nature, and abstract scenes provide different visual structures instead of repeating one recolored geometric template. Each puzzle has one defined hotspot and one intended change.

Everything outside the intended object remains stable. The scene illustration is generated from project-owned vector code, so no stock photograph, competitor puzzle, or standardized test material is used. Alternative text describes the scene without disclosing the answer.

A local motion signal can normally draw attention to a change. Placing a neutral interruption between scene A and scene B weakens that signal, so the viewer may need to search object by object. A detail can be visible in both versions and still take time to locate.

Rensink, O’Regan, and Clark’s 1997 flicker-paradigm paper reported that changes became difficult to identify when brief blank fields separated alternating scenes. This page demonstrates a related mechanism with gentle, contained transitions; it does not reproduce their materials or turn a research finding into a claim about training benefits.

Timing uses performance.now() and stops on the first click inside the defined hotspot. A click outside the hotspot increments the incorrect-click count but does not reveal the answer. The exact first-click rate is the percentage of completed puzzles solved on the first click.

The summary reports the median of solved-puzzle detection times rather than an average that can be dominated by one long search. No trial is silently removed. Leaving the tab pauses the scene and adds a focus-interruption validity flag; an incomplete or restarted run is not saved as a normal completion.

A hint draws a broad ring around the region containing the change. It does not name the object, but it reduces the area that must be searched. For that reason, puzzles solved with and without a hint are counted separately.

A hint-assisted time is still useful for understanding the current puzzle, but it should not be compared directly with an unassisted time. Standard mode limits the practical value of repeated hints by exposing their use in the results instead of blending every solve into one score.

Automatic mode alternates scenes on a fixed comfortable interval. Slower mode lengthens that interval. Manual mode replaces animation with an explicit A/B button, which is also selected when the browser reports a reduced-motion preference.

Manual switching changes how long each scene is inspected and lets the viewer control the transition, so its times are not directly comparable with automatic mode. The selected switching method and speed are saved with the completed session.

A small phone compresses details and a mouse allows different pointing precision than a finger. Display scaling, brightness, color rendering, interruptions, and familiarity with a puzzle can all change the result. Compare personal sessions only when mode, switching method, device, and input are similar.

Missing a detail does not show a visual or cognitive defect. This is a simplified browser task with a finite original puzzle set, not an eye examination or clinical change-detection procedure. Consult a qualified professional for concerns about vision or health rather than interpreting this page as a screen.

Rensink, R. A., O’Regan, J. K., & Clark, J. J. (1997). “To See or not to See: The Need for Attention to Perceive Changes in Scenes.” Psychological Science, 8(5), 368–373. https://doi.org/10.1111/j.1467-9280.1997.tb00427.x