The most intriguing result in the present study is thepositive effect of white noise on performance for theADHD children. This noise effect was present in boththe non-medicated and medicated children. Thissupports the MBA (Moderate Brain Arousal) model(Sikstro ̈m & So ̈derlund, 2007), suggesting that theendogenous (neural) noise level in children withADHD is sub-optimal. MBA accounts for the noise-enhancing phenomenon by stochastic resonance(SR). The model suggests that noise in the environ-ment introduces internal noise into the neural sys-tem through the perceptual system. Of particularimportance, the MBA model suggests that the peakof the SR curve depends on the dopamine level, sothat participants with low dopamine levels (ADHD)require more noise for optimal cognitive performancecompared to controls.

It has long been known that cognitive processing iseasily disturbed by noise and other distractors(Broadbent, 1958).

The MBAmodel predicts that noise enhances memory perfor-mance for ADHD and attenuates performance forcontrols. We will also argue for a link between theeffects of noise, dopamine regulation, and cognitiveperformance.

Results: Noise exerted a positive effect on cognitive performance forthe ADHD group and deteriorated performance for the control group, indicating that ADHD subjectsneed more noise than controls for optimal cognitive performance