Extreme size change in a shared element distorts identity

What it is

Stretch a 24-pixel icon into a full-screen photograph and the in-between frames look like neither. When the scale span is too large, the shared element is no longer read as “the same object getting bigger”; it is read as a material being pulled. Identity continuity needs a still-recognisable surface during the morph; once scale strips recognisability, the weld becomes distortion.

Why it happens

An object file depends on matchable surface features: silhouette, texture scale, crop. Linear magnification invents high-frequency detail from nothing, or tears existing detail into patches. Mid-frame spatial frequencies match neither end, correspondence loses its anchors, and the visual system falls back to “a rectangle is inflating,” dropping the object’s label.

A changing aspect ratio makes the stretch non-similar: faces and type undergo non-rigid warp, which looks even less like the same object than uniform growth. Different crops (centre-crop in the list, full composition on detail) make mid-frames grow or eat content, further breaking “still that picture.”

Studying it

Vary start-to-end size ratio, aspect-ratio gap, and whether the crop changes; ask whether it is “still the same / became something else,” and test recognition of isolated mid-frames. Independent variables: linear scale ratio, aspect-ratio delta, content type (faces, type, flat colour). Dependent variables: identity-preservation ratings, mid-frame recognition, discomfort. Faces and type are more sensitive to non-rigid warp.

Where it stops holding

• Flat colour or extremely simple icons can survive large scale change because there is no texture to tear.
• Blurry or low-detail covers survive enlargement better than sharp photographs.
• Modest scale change over a very long spatial path fails as tracking, not as distortion — that is a distance–duration problem, not this one.

Applying it

• Prefer a primary visual whose scale span is bounded. Do not stretch an icon into a full-screen photo; share the photo itself and leave the icon in place.
• Lock aspect ratio; fill the end state by cropping, not by non-uniform stretch.
• Check: inspect mid-frames on their own. If the original item cannot be recognised, or faces and type warp, drop the shared element for a fade or a small displacement.

Related

• Same group: F7.04.1 A shared element keeps the object's identity continuous · F7.04.3 When a shared element cannot map, fall back to an ordinary transition
• Nearby: F7.02.3 Larger travel needs a longer duration · A1.27 Perceptual constancy
• Search terms: scale distortion · shared element · non-rigid transform