Geons and Bubbles: Object recognition by pigeons

Abstract

We trained three pigeons to recognize four shaded, unoccluded geons (arch, barrel, brick, wedge) using a four-key forced-choice discrimination task. When the pigeons mastered the discrimination task to a very high level of proficiency, they were presented with geon images that were partly revealed by a mid-grey mask punctured by a number of randomly located Gaussian windows (‘bubbles’; Gosselin & Schyns, 2000). We used several sets of bubbles images, with different number of bubbles per image, that revealed different amounts of visual information to the pigeons. Bubbles analysis disclosed that the pigeons attended to the edges of the geons, confirming one of the predictions of recognition-by-component theory (Biederman, 1989). The pigeons also appeared to be attending to some surface features, such as a bright spot on the surface of one of the geons.

Footnotes

 This research was supported by National Institute of Mental Health Grant MH47313.