Carrasco, M. & Sekuler, E.B. (1993). An unreported size illusion. Perception,
A previously unreported size illusion in some commonly used stimuli- a
large (global) letter made up of small (local) letters (eg a large H made
up of small Es) is described: the size of the local letters forming the
horizontal component of the global letter appears to be overestimated.
Global and local letters made up of horizontal and vertical components
(E, F, T, and H) were employed as stimulus material. The first experiment
showed that the illusion was consistently perceived, and was present for
most of the stimuli tested; ie for all global letters and for all local
letters except H. A second experiment showed that the size distortion
is not specific to a particular dimension: instructing observers to focus
on the height of the width of the local letters did not affect the extent
of the illusion. The effect of some stimulus manipulations was also investigated.