Recent advancements in digital technologies have improved the ability to reproduce high-fidelity sound. This study examined the effects of binaural sound, which more accurately recreates the original sound field than monaural sound, on psychophysiological responses. Thirty-four university students completed a visual two-choice reaction time task while listening to two types of sound: a binaural recording of ocean surf and its monaural version created by averaging the left and right channels. To assess physiological states, electroencephalograms (EEG), event-related potentials (P300), electrocardiograms (ECG), and respiratory activity were recorded. Participants perceived binaural sound as deeper, wider, and softer than monaural sound and were more likely to rate it as a comfortable and natural stimulus. However, behavioral and physiological measures showed no significant differences between the two sound conditions. These findings suggest that merely perceiving differences between the two sounds may not be sufficient to demonstrate psychophysiological effects. Future research should be conducted under conditions (e.g., sound type and listening environment) where the characteristics of binaural sounds become more distinct.