Date of Award
8-2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
School
Psychology
Committee Chair
Alen Hajnal
Committee Chair School
Psychology
Committee Member 2
Mark Huff
Committee Member 2 School
Psychology
Committee Member 3
Kenji Noguchi
Committee Member 3 School
Psychology
Committee Member 4
Lin Agler
Committee Member 4 School
Psychology
Abstract
People can orient and configure their hands in many ways in order to grasp objects. The current study investigates how object shape and hand placement influence graspability of objects, and how experimentally imposed constraints on grasping type alter grasping behavior. In a recent study, Gunter and Hajnal (under review) found that the ratio of object curvature and maximal handspan is the variable that defines the affordance of graspability. The current study aims to extend these findings by employing a more precise measurement of finger placement in two experiments using 3D printed objects as stimuli. To capture varying complexities of object shape, the stimuli for both experiments included rectangular prisms, ellipsoids, replicas of potatoes, and bell peppers. In both experiments, participants grasped and lifted the objects off of a table with one hand. The task in Experiment 1 was exploratory, with no restrictions on how to grasp the objects. The goal of Experiment 1 was to explore natural grasping behavior of different irregular objects and determine the best measure to quantify the graspability of irregular shapes. In Experiment 2, participants were restricted to grasp the objects from the top along their short axes of rotation, replicating the procedure in our recent study (Gunter & Hajnal, under review). The variables that define graspability depended on grasping manner and on the complexity of object shape. The ratio of curvature and handspan was the best predictor of graspability irrespective of manner of grasp and restrictions on exploratory behavior. Eye movements were also predicted by the proposed ratio.
ORCID ID
0009-0007-4973-9999
Copyright
McKenzie Gunter 2026
Recommended Citation
Gunter, McKenzie, "The Influence of Shape Complexity and Exploratory Behavior on Grasping" (2026). Dissertations. 2488.
https://aquila.usm.edu/dissertations/2488