Gaze Parameters in the Analysis of Ambiguous Geometric Shapes.

Linda Krauze,Jurgis Skilters,Baingio Pinna,Ilze Ceple,Gunta Krumina,Mara Delesa–Velina

doi:10.1177/2041669521998392

Linda Krauze, Jurgis Skilters + Show 4 more

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https://doi.org/10.1177/2041669521998392

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Journal: i-Perception	Publication Date: Mar 1, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: University of Latvia, University of Sassari

Abstract

This study explores perceptual organisation and shape perception when viewing a tetragon and an additional element (a dot) that is located at varying positions and distances next to the tetragon. The aim of the study is to determine the factors that can alter the interpretation of object configuration and impact whether the presented tetragon is perceived as a diamond or a square. Methods used in this study are a forced-choice task as a subjective measurement and eye tracking as an objective measurement of perceptual processes. Overall, 31 stimuli were presented to the participants: a tetragon in two different sizes with an additional element (a dot) located inside or outside the object at three different positions at three distances. The results indicate significant changes in shape perception, depending on the location of the additional element. The results are complemented with eye movement analysis indicating that as the distance between the elements increases, there is a higher probability of either of the two shape interpretations and the gaze is less likely to be directed to the area between the stimuli. Furthermore, the subjective perception of shape is codetermined by the shape perception when the tetragon is presented without the additional element.

Highlights

Perceptual organisation is the key for constructing a coherent visual percept of the external environment
Based on the principles of visual grouping and gaze processing in visual grouping, it was hypothesised that the placement of an additional element at different locations might have an impact on the shape assignment and may influence the resulting shape perception
The results demonstrate the effect of grouping on the shape perception previously described by Pinna (2010, 2015), indicating that an additional element can affect the perception of a tetragon by perceiving it as a diamond or a square depending on the position of the additional element

Summary

Introduction

Perceptual organisation is the key for constructing a coherent visual percept of the external environment. It refers to the way we process sensory input based on the levels of luminance or separate shapes, edges, and lines and to the way we segment this information, by creating distinct objects or groups of objects in our percept. The questions regarding why we see the world exactly as we see it, what determines the processing of visual information and how objects and their forms are perceived and analysed have been extensively studied before (see Palmer, 1999; Wagemans, 2015 for overviews). Since different studies have demonstrated principles underlying the ways individual elements are grouped into larger wholes (Pinna, 2010, 2015; Wagemans et al, 2012). Gestalt principles of visual grouping provide important guidance on what element properties enable perception of wholes: these properties include proximity, similarity, good continuation, closure, convexity, symmetry, as well as past experience (Brooks, 2015)

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