BEHAVIORAn invisible sign stimulus completion of occluded visual images in the Bengalese finch in an ecological contextTakahasi, Mikia,b,c; Okanoya, Kazuoa,c,d,eAuthor Information aDepartment of Cognitive and Behavioral Sciences, Graduate School of Arts and Sciences, University of Tokyo bJapan Society for the Promotion of Science, Tokyo cDepartment of Cognitive and Information Sciences, Faculty of Letters, Chiba University, Chiba dERATO Okanoya Emotional Information Project, Japan Science and Technology Agency, Saitama eRIKEN Brain Science Institute, Saitama, Japan Correspondence to Kazuo Okanoya, PhD, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, Japan Tel: +81 3 5454 6266; fax: +81 3 5454 6725; e-mail: [email protected] Received February 4, 2013 Accepted February 27, 2013 NeuroReport: May 8, 2013 - Volume 24 - Issue 7 - p 370-374 doi: 10.1097/WNR.0b013e328360ba32 Buy Metrics Abstract An object that includes occluded parts is sometimes perceived as a complete image and this phenomenon is known as amodal or visual completion. A sign stimulus is a minimum set of information that elicits a behavior, but this notion raises questions about whether animals ever engage in the behavior when they cannot see the occluded sign stimulus, but they can visually complete it. Male Bengalese finches engage in courtship behavior toward video images of female finches. We conducted three experiments with Bengalese finches to show both sign stimuli and visual completion function in an ecological context. We used three types of visual images recorded from female finches as stimuli: the head, the body, and the whole. Results showed that male Bengalese finches showed courtship behavior toward the head-occluded stimuli whereas they did not toward the headless body image. The results imply that the males completed this occluded sign stimulus through the process of visual completion. Exposure to a sign stimulus combined with the process of visual completion may operate cooperatively to facilitate adaptive responses under conditions of limited information. © 2013 Lippincott Williams & Wilkins, Inc.