Auditory Asymmetry Localization Theory_ A General Evolutionary and Spatial Sound Source Adaptation Hypothesis for Auditory Organisms

Abstract Traditional auditory localization relies exclusively on interaural time difference (ITD) and interaural intensity difference (IID), which inherently cause front–back and vertical spatial ambiguities and fail to fully explain the precise three-dimensional sound localization abilities of auditory organisms. Bilateral auditory structural asymmetry across species has long been misregarded as random developmental noise, while its adaptive evolutionary function remains underexplored. To address the theoretical gap in universal auditory localization mechanisms, this study proposes the Auditory Asymmetry Localization Theory (AALT), a cross-taxa evolutionary hypothesis grounded in evolutionary biology and bioacoustics. This work verifies that cross-species auditory asymmetry is a heritable, adaptive trait fixed by natural selection, rather than trivial developmental variation. It further defines the endogenous Auditory Structural Spectrum Difference (ASSD), which acts as a third core localization cue synergizing with ITD and IID to eliminate traditional spatial blind spots and achieve full-dimensional sound localization. This study reveals a unique auditory evolutionary paradigm featuring fixed bilateral auditory organs and adaptive structural asymmetry, distinctly different from visual system evolution. The proposed theory resolves long-standing academic biases regarding auditory asymmetry, offering novel theoretical support for paleontological sensory reconstruction, bionic auditory design, and clinical audiological optimization.