Grouping and search efficiency in emergent features and topological properties in human vision
Portillo, Mary C.
Pomerantz, James R.
Doctor of Philosophy
A series of three experiments were designed to test for Emergent Features, which, in Gestalt psychology, are indicative of grouping. By using basic elements such as dots or lines and building EFs sequentially, while maintaining the original discrimination constant, it was possible to compare the strength of different EFs. Proximity, Orientation, Symmetry, Linearity, Surroundedness, Inside/Outside relationship, Collinearity, Parallelism, Inflection Point and Closure were tested. A Configural Superiority Effect (CSE, where the RT in a composite condition is shorter than the RT in a singleton condition) was diagnostic of the presence of an EF in an Odd Quadrant task. Proximity, Orientation, Linearity, inside/Outside and Collinearity produced CSEs and thus behave as basic in human vision. Mixed results were obtained for Symmetry and Parallelism. Further, Inflection Point and Closure were only suggested in the stimuli, so they cannot be ruled out as EFs.
Experimental psychology; Cognitive psychology