Pink noise drops 3 dB per octave, producing equal energy per octave. This matches how the human ear perceives pitch, making it sound more balanced and natural than white noise. It is widely used as the reference signal for audio system calibration.
The Nigg et al. (2024) meta-analysis explicitly includes pink noise alongside white noise, finding the same direction and magnitude of benefit for ADHD performance. Pink noise is one of the most commonly observed signals in biological systems, appearing in heartbeat rhythms, neuron firing patterns, and tidal fluctuations (Voss & Clarke, 1975).
Rijmen & Wiersema (2024) found that pink noise improved reaction time performance in adults with ADHD traits. Lu et al. (2020) found pink noise was the only color that significantly improved sustained attention in a general-population sample.