Perceiving Events and Objects

Perceiving Events and Objects

Perceiving Events and Objects

Perceiving Events and Objects


Beginning with his doctoral dissertation in 1950 which introduced the study of event perception and the application of vector analysis to perception, Gunnar Johansson has been a seminal figure in the field of perception. His work on biomechanical motion in the 1970s challenged conventional notions and stimulated great interest among experimental psychologists and students of machine vision. In 1989 Johansson published his latest theoretical synthesis, the optic sphere theory, an innovative conceptualization that goes beyond his earlier proposals.

This volume presents -- for the first time -- an extensive precis of the out-of-print classic 1950 monograph prepared by Johansson. It also includes a representative set of Johansson's important publications produced over the ensuing four decades. These papers served as the springboard for a set of original essays by a distinguished group of North American and European scientists. Part critical commentary, part elaboration, and part seeking new directions, the entire collection makes for a singularly rich treatment of the perception of objects and events.


In 1989, at the age of 78, Gunnar Johansson, together with his collaborator and former student Eric Börjesson, published a paper called "Towards a new theory of vision. Studies in wide-angle space perception" (Ecological Psychology, 1, 301-331). This was the first presentation of the optic sphere theory. The title chosen for that paper was neither modest nor incidental. The paper started intense discussions, at least among Swedish perceptionists.

Gunnar Johansson has had a long and productive career as an experimental psychologist in visual perception. Gunnar's doctoral dissertation, with David Katz as his mentor, introduced the perceptual vector analysis, which has inspired much research and discussion not only in Gunnar's own laboratory but worldwide. The dissertation opened the international window for Gunnar and brought him in contact with Gestaltists like Wolfgang Köhler and Hans Wallach and also with James Gibson. (Remember that this happened shortly after World War II, with all the isolation that meant!). Gunnar's later studies on vector analysis and depth perception, the first one when visiting James Gibson's laboratory, inspired a number of doctoral dissertations at Uppsala. And his more recent studies on the perception of biological motion became the starting point for many studies in several laboratories. But what about the optical sphere theory?

Since Gunnar does not like Festschriften we decided to celebrate his 80th birthday by arranging a symposium on the optic sphere theory. Gunnar agreed to this type of celebration on certain conditions: (a) there should be a small number of sophisticated contributors invited, and (b) those invited should read his theory and criticize it rather than act as devotees or present their own work. This is a very typical Gunnar Johansson reaction. He would never agree to a symposium just to celebrate himself. It has to contribute to the development of theory.

Some of the invited American scientists suggested, however, that the status of the vector analysis model after four decades should be discussed, so we talked Gunnar into accepting a discussion of "that old stuff" too.

The symposium was held at the Department of Psychology, Uppsala University, Uppsala, Sweden, August 21-23, 1991. To get acquainted with the optic sphere theory all the participants got a lot of written material, both published and unpublished, well in advance. The contributors to the symposium also exchanged preliminary versions of their contributions in order to optimize the conditions for good scientific discussions. At the end of the symposium the participants were excited enough to unanimously decide to collect their contributions in a book. It was also suggested that such a volume should include the main part of Gunnar's dissertation, "Configurations in Event Perception," which . . .

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