Positive effects of noise on cognitive performance: Explaining the moderate brain arousal model

Distractors and environmental noise has long been regarded as detrimental for different kinds of cognitive processing. In particular children with Attention Deficit Hyperactivity Disorder (ADHD) are extremely sensitive to distraction from task irrelevant stimuli. However, recently the opposite has been shown in an empirical study by Söderlund et al. (2007). Exposure to auditory white noise facilitated cognitive performance in ADHD children whereas control children performed worse in the noise condition. The mechanisms behind this paradoxical effect is described by the moderate brain arousal (MBA) model (Sikström & Söderlund, 2007) where the selective effect of noise is accounted for by the phenomenon of stochastic resonance (SR). Stochastic resonance exists in any threshold-based system with random noise that requires passing of a threshold, e.g. the all or none nature of action potentials in neural systems. The basic assumption is that noise in the environment, through the perceptual system introduces internal noise in the neural system. According to the SR phenomenon moderate noise is beneficial for cognitive performance whereas both excessive and insufficient noise is detrimental. The MBA model suggests that dopamine levels modulate the amount of noise required for optimal cognitive performance. The model prediction is that low dopamine children, as in ADHD, require more noise as high dopamine children for optimal cognitive performance; in short, when dopamine is low noise is good