Influence of Head Sway on the Availability of Visual Information in an Affordance Task

This thesis investigated how varying postural conditions and environmental challenges influence human affordance perception in virtual environments, focusing specifically on participants’ judgments about whether they could stand upright on sloped surfaces. Using virtual reality (VR) to simulate ramps at various inclines, participants assessed their ability to stand on these slopes under different postural constraints (unaided standing, leaning, and touch-supported). Data was collected on head movement dynamics, including movement magnitude, variability, and complexity, using measures such as Euclidean distance and effort-to-compress (ETC). Logistic and linear regression analyses revealed that slope angle and stance significantly impacted participants' affordance judgments and movement patterns, with increased slope angles correlating with decreased affirmative responses and greater head movement complexity, particularly around critical angles near 30 degrees. These findings suggest that exploratory movement patterns become more complex as individuals approach the limits of perceived affordances, highlighting the functional specificity of perception in relation to task demands.