Boundary Extension

What is boundary extension?

Boundary extension is remembering a scene as including visual information beyond the area originally shown.

Boundary extension example and measurement

Imagine seeing a tightly cropped photograph of a table. Later, you remember a little more of the surrounding room than the photograph showed. The remembered view has extended beyond the original boundaries.

Intraub and Richardson’s 1989 experiments found the effect in drawings and recognition of photographed scenes. It is a distortion relative to the presented image, even if the added content is plausible.

Boundary extension and boundary contraction

Extension is not universal. Bainbridge and Baker’s 2020 study used 1,000 images and 2,000 participants and found both extension and contraction. Image composition influenced the direction: object-focused images tended toward extension, while wider scene-focused images tended toward contraction.

The remembered view can therefore move in either direction. The image’s composition matters. Researchers continue to debate how scene construction contributes to these patterns.

The practical point is about the accuracy of visual memory. A plausible surrounding detail may feel like something you saw.

The Perky effect offers a related comparison between visual perception and mental imagery.