The ’Footsteps Illusion’ shows that pitch-altering footstep sounds in real-time affects body perception, gait, and emotion: high versus low frequencies evoke a lighter versus heavier body. We tested whether this illusion extends beyond the lab, where environmental factors matter. Using a mixed-methods approach, twenty-eight participants used a minimal setup to synchronize with three prerecorded pitch-altered footstep soundtracks: Control, High-Frequency, and Low-Frequency. In Experiment 1, they walked a fixed path, with gait recordings, questionnaires, and body visualizations. In Experiment 2, they walked freely across campus routes with High/Low-Frequency soundtracks, followed by post-walk interviews using a novel spatial mapping tool linking body sensations to context. Results replicate the illusion outdoors, showing synchronization with prerecorded sounds as a viable alternative to real-time feedback, and revealing that contextual factors modulate illusion effects. We contribute insights and novel tools (prototype, spatial mapping method, and footstep soundbase) for studying multisensory body perception in everyday contexts.

Researching body experiences poses challenges due to their inherently subjective and intangible nature. In TEI, more broadly in HCI, methods like body maps capture these experiences. We advance body maps by developing and applying two extensions to body maps to address important dimensions of body experience. These were tested in two studies. The first focuses on design processes aimed at achieving more generalizable data through quantitative methods, while enabling analysis from an individual perspective. Here, we introduce a segmentation approach of body maps for quantifying and comparing body experiences. These maps feature subdivisions of various body areas, derived from a study reporting the effects of movement sonification intervention on body perception. The segmentation allows for precise measurement and comparison of these changes. In the second, we shift to the context in which body experiences take place, presenting context-sensitive body maps anchored in the environment. These maps explore the relationship between body and environment. We present methodologies for researching embodied interactions within TEI.

Changes in body perception influence behavior and emotion and can be induced through multisensory feedback. Auditory feedback to one’s actions can trigger such alterations; however, it is unclear which individual factors modulate these effects. We employ and evaluate SoniWeight Shoes, a wearable device based on literature for altering one’s weight perception through manipulated footstep sounds. In a healthy population sample across a spectrum of individuals (n=84) with varying degrees of eating disorder symptomatology, physical activity levels, body concerns, and mental imagery capacities, we explore the effects of three sound conditions (low-frequency, high-frequency and control) on extensive body perception measures (demographic, behavioral, physiological, psychological, and subjective). Analyses revealed an impact of individual differences in each of these dimensions. Besides replicating previous findings, we reveal and highlight the role of individual differences in body perception, offering avenues for personalized sonification strategies. Datasets, technical refinements, and novel body map quantification tools are provided.