Research in spatial audio has traditionally focused on localization accuracy, spatial realism, and rendering algorithms. Comparatively little work has examined how intentionally designed spatial audio environments may influence listener physiological regulation and emotional perception. This paper introduces the concept of Social Sonic Design, a framework that examines how spatially organized sonic information within and external to XR contexts may affect autonomic nervous system response and autobiographical memory. Spatial audio cues such as proximity, elevation, and diffuse reverberation influence listener perception of environmental stability and safety. Building on these perceptual principles, the present study investigates whether object-based audio environments incorporating temporally structured and personally meaningful sound materials can influence listener physiological state. Spatial audio infrastructures were constructed from lullabies, caregiving vocalizations, and environmental sonic textures. Postpartum mothers were selected as an initial participant group because caregiving sound environments and lullaby traditions play a central role in maternal–infant interaction and emotional regulation. Immersive sonic infrastructures were produced using spatial audio capture and design techniques including Dolby Atmos multichannel rendering (7.1.2) and binaural headphone reproduction. Sound sources were modified to activate three targeted neuro-cognitive nodes and spatially distributed across the listening environment to create immersive auditory scenes incorporating foreground vocal sources, diffuse environmental textures, and spatialized reverberant fields. Participants experienced these environments in brief episodic listening sessions accompanied by visual media. The episodic presentation structure draws inspiration from media models such as those developed by Miguel Sabido, in which repeated exposure to idealized sensory environments may influence perception and behavioral response over time. Physiological responses were monitored using measures associated with autonomic nervous system activity, including heart rate and heart rate variability (HRV), alongside reports of perceived calm, emotional response, and autobiographical memory recall. Preliminary observations suggest that the sonic infrastructure of immersive lullaby environments evokes caregiving memories and perceived emotional grounding among participants, indicating that spatially designed sonic environments may contribute to changes in listener perception and physiological regulation.
