The effect of sound on visual perception: An experimental study through virtual reality spaces

The spatial environment is an existential domain intertwined with time and is directly related to how individuals position themselves in the world. Beyond merely constructing physical enclosures, architecture plays a significant role in shaping this existential experience and contributes to the ontological formation of spatial settings. Understanding how the built environment is perceived—and how this perception is expressed—constitutes a critical area of inquiry within architectural discourse. While visual perception is often regarded as the dominant sensory input, cognitive outcomes may vary significantly when multiple senses are engaged simultaneously. In this context, the research is grounded in the hypothesis that volumetric qualities shaped through the integration of light and sound can generate lasting memory traces through a harmonic and optical experience. The aim of the study is to examine the interaction between visual and auditory stimuli and how this interaction affects the perception and memory of architectural environments. To this end, an interactive virtual reality experiment was developed based on spatial typologies drawn from architectural literature. Three primary types—bounded, sensory, and memory-based environments—were designed and expanded through formal and material variations. A total of 36 rooms were modeled in 3ds Max and Rhino Grasshopper and developed in Unreal Engine 5.3. These rooms incorporated formal diversity, material differentiation, and volumetric variation. Participants experienced these environments accompanied by isochronic tones in alpha, beta, and delta frequencies. Acoustic reverberation times were calculated using Sabine's formula, and light durations were synchronized accordingly, allowing the sound to function as a luminous element that enhanced multisensory perception. The study involved 28 participants—architects and architecture students with varying levels of experience—who engaged in 25-minute sessions. Their responses were evaluated based on how effectively they perceived the spatial environments, the elements retained in memory, and how these related to sound frequency. Results from post-experience questionnaires revealed that dynamic auditory stimuli enhanced cognitive engagement in complex spatial forms, while slower rhythms promoted perceptual clarity and emotional calmness in simpler environments. The findings suggest that sound can function as a guiding, cognitive, and affective design element in architecture. This study, which shows that experiencing the space visually along with repeated sounds increases short-term visual-spatial working memory and cortical connectivity, can provide data for perception studies in wider virtual spaces by enriching them with different parameters.