One-page summary

PhD researcher: Van Geert Eline
Title of the research
project:		 Prägnanz in visual perception: Towards better theories,
measures, and tests of good Gestalts
Supervisor: Prof. Dr. Johan Wagemans
Proposed members of the
mid-term evaluation
committee:		 * Prof. Dr. Wolf Vanpaemel (KU Leuven)
* Prof. Dr. Hans Op de Beeck (KU Leuven)
* Prof. Dr. Floris de Lange (Radboud University)
* Prof. Dr. Mark Wexler (Université Paris Descartes)
* Prof. Dr. Vebjørn Ekroll (University of Bergen)
Interactive version of report: https://elinevg.github.io/pragnanz_in_visual_perception/
password: gestaltrevision

Things look as they do not only because of the visual input an individual receives, but also because of how the viewer processes this input in a certain context. Prägnanz is about how viewers organize the inputs and about why that is the case. Traditionally, the law of Prägnanz is formulated as follows: “[…] psychological organization will always be as “good” as the prevailing conditions allow” (Koffka, 1935, p. 110).

In this project, we develop a more fine-grained understanding of Prägnanz (i.e., “goodness” of organization) and its added value for current theory and research on human visual perception, both by studying the existing literature and conducting new empirical research. The proposed empirical studies concern the relation of Prägnanz with: (a) robustness and sensitivity to change; (b) hysteresis and adaptation; (c) order and complexity; and (d) simplification and complication. Each of those concept pairs are partial opposites as well as partial complements, as they tend to decrease each other’s influence but also work together towards a better psycho-physical organization. What this ‘better’, more prägnant organization will be, will depend on the individual in question, the input the individual receives, as well as the context in which the individual receives the input.

Chapter 3 studies whether and how the robustness and sensitivity of prägnant Gestalts that are used as reference points influence percept formation and consequently performance in categorization, discrimination, and similarity judgment tasks. Chapter 4 investigates how attractive and repulsive effects of immediate perceptual and stimulus history can alter what we perceive and what the best organization of the input will be. In addition, we examine whether the size of these context effects systematically varies across individuals, and if so, how these differences relate to more high-level interindividual differences in personality characteristics and more low-level differences in prägnant steps on feature dimensions. In Chapter 5, I hypothesize that some forms of aesthetic appreciation are related to an increase in Prägnanz (i.e., increase in order and/or complexity) rather than to Prägnanz as such, with a minimum level of order as a prerequisite for appreciation. Also, I discuss how individual differences in Prägnanz and aesthetic appreciation may be partly due to different optimal combinations of order and complexity levels. Furthermore, a new tool to study the relation between order, complexity, Prägnanz, and aesthetic appreciation is presented. Chapter 6 details future research ideas on how a combination of removing unnecessary details (i.e., simplification) and emphasizing characteristic features (i.e., complication) can increase the Prägnanz of a Gestalt and as a result also influence higher-order processes.

Online documentation appending some of the projects discussed in this mid-term report can be found on Open Science Framework: https://doi.org/10.17605/OSF.IO/7RSYF.