The meaning of graphs: scatterplots as a test-bed for theories of object-hood

The burgeoning field of visual analytics offers a novel area for research in principles of Gestalt, specifically in the definitions of object-hood. Abstract visualisations are parsed into perceptual objects that are rich in meaning, the meaning that is based on spatial configuration of these objects and their elements, yet completely devoid of physical restrictions and connotations. The ‘Pop-out’ paradigm offers an objective testing methodology for the processes of visual scene parsing and onto formation of high-level semantics and pragmatics, i.e. meaning, of the scene. An experiment is presented that applies the ‘pop-out’ paradigm to trend detection in a 3D scatterplot. The experiment addresses the question: “what constitutes an object in a scatterplot?”, and in doing so dissociates between two conflicting theories of perceptual organisation: the Feature Integration Theory and the Reverse Hierarchy Theory, in favour of the Reverse Hierarchy Theory.