The tenacity of historical misinformation: Titchener did not invent the Titchener illusion.

Abstract

Some well-known psychological facts are actually false, but dispelling them is difficult. One such false fact is that Titchener introduced the illusion depicting a circle ringed by smaller circles, which appears larger than an equivalent circle surrounded by larger circles. A review of contemporary sources indicates that Ebbinghaus probably introduced this illusion in the 1890s, although not in any explicit publication, and Titchener neither had nor asserted any authorship of this figure. There are also 3 other illusions that are sometimes labeled the Ebbinghaus illusion. The modern custom of attributing the surrounded-circles illusion to Titchener, although widespread in the 1960s and 1970s, does not appear before 1957.