Delboeuf illusion

[1] The illusion was named for the Belgian philosopher, mathematician, experimental psychologist, hypnotist, and psychophysicist Joseph Remi Leopold Delboeuf (1831–1896), who discovered it in 1865.

[4] In 2012, Ittersum and Wansink published a study that hinted to the Delboeuf illusion as a factor in increased food servings.

These researchers suggest that these findings are potential grounds for mitigating the use of the Delboeuf illusion as a dieting aid.

[9] Miletto-Petrazzini, Bisazza and Agrillo (2016) replicated the study conducted by Parrish and Beran (2014) but used dogs as the participants instead of chimpanzees.

The authors went on to discuss how this may hint towards the dogs' reactions to the Delboeuf illusion as a matter of assimilated learning.

[11] Bearded dragons and red-footed tortoise were both studied to understand if these species can perceive the Delboeuf illusion.

Bearded dragons showed action that suggests that they perceive the illusion in a way similar to humans.

The tortoises however, showed no preference for larger portions (a similar problem found in the study of ring-tailed lemurs) and were thus not testable by the method that had been outlined by the test designers.