Born to a Hungarian father and a Slovene mother, he attended the classic lyceum, and got the laurea (post-secondary academic degree) at the University of Padova in 1938, writing a thesis about eidetic memory. In 1947 he became a teaching assistant in the University of Florence. In 1953 he returned to Trieste with the role of full professor, which he held for 30 years. He retired from academic life in 1988 and continued research until 1993, the year of his death.
A dominant figure in Italian psychology, Kanizsa became famous in the 70s, after having published an article about illusory contours (Scientific American, 1976) and the book Organization in Vision (1979). A figure in which three illusory contours form a triangle is known as a Kanizsa triangle.
To his scientific interest, Kanizsa added his painting activity.
- Organization in Vision: Essays on Gestalt Perception, Praeger Publishers, 1979, ISBN 0-275-90373-7
- Percezione, linguaggio, pensiero (Perception, speech, thought) by Gaetano Kanizsa, Paolo Legrenzi, M. Sonino, Il Mulino, Bologna, 1983
- Vedere e pensare (Seeing and thinking), Il Mulino, Bologna, 1991
- Some of Kanizsa's paintings on http://www.psico.univ.trieste.it/kanizsa/catalogo/catalogo.php3