Environmental Noise Alters Neural Regulation Without Behavioral Impairment: A Pilot EEG Study

Environmental factors can profoundly influence cognitive performance and well-being in the workplace. Exposure to environmental noise is a potent stressor that elevates arousal and impairs attention, whereas natural elements are associated with stress reduction and cognitive restoration. In this pilot study, we examined whether natural soundscapes could buffer the neural effects of noise exposure. Eleven healthy adults performed five cognitive tasks, Stroop, N-back, Go/No-Go, Dot-Probe, and Visual Search, under three auditory conditions: Noise (simulated urban traffic), Nature (ambient natural sounds), and Control (silence with earplugs). Continuous electroencephalography (EEG) captured oscillatory activity, and participants provided self-reports of mood, stress, and lifestyle habits. Behavioral accuracy and reaction time did not differ significantly across environments (all p > 0.10), indicating preserved overt performance. However, EEG revealed clear environment-dependent modulation. Relative to Control, the Noise condition produced a marked shift toward beta-dominant activity in midline cortex: mixed-effects models showed higher α/β ratios over central (t = 3.8, cluster-corrected p < 0.01) and centroparietal (t = 4.6, p < 0.01) regions, reflecting reduced posterior α power and a sustained-alertness profile. In contrast, Nature exposure preserved posterior α regulation while easing cognitive-load markers, θ/α ratios fell in bilateral temporal cortex (t = −3.2, p < 0.05), θ/β ratios dropped across frontocentral and temporal networks (t = −3.6 to −7.4, p < 0.01), and the engagement index rose in the same territories (t = −3.6 to −7.3, p < 0.001), consistent with greater intrinsic engagement and lower self-reported stress during the nature soundscape. Although behavioral performance remained stable, EEG data revealed distinct neural costs of noise exposure and a protective effect of natural soundscapes. These findings suggest that traditional task metrics may underestimate cognitive strain, and that biophilic auditory environments could help sustain neural efficiency and resilience in demanding work settings.