Attentiveness interacts with the effect of transcranial direct current stimulation and white noise on cognitive performance

Abstract: Scarce research has been conducted on the moderating role of attentiveness in the effect of tDCS on cognitive performance. On the other hand, research on the impact of auditory noise on attention has generally demonstrated the detrimental effect of task-irrelevant noise on performance of cognitive tasks, yet has also neglected to explore the role of attentiveness in this relationship. Accordingly, the current study examined whether attentiveness moderates the effect of white noise (WN) and transcranial direct current stimulation (tDCS) on cognitive performance. Twenty-four participants were split into a ‘low attentiveness’ group and a ‘high attentiveness’ group based on how they scored on the SNAP-IV attention subscale. Both groups completed the Cued Go/No-Go Task under three stimulation conditions: No-noise, WN, and tDCS. Reaction time and accuracy in the task were recorded. It was hypothesized that the ‘low attentiveness’ group would perform better in the WN and tDCS conditions, whereas the ‘high attentiveness’ group would perform worse in the WN and tDCS conditions, compared to the no-noise condition. These hypotheses were derived from the MBA model that suggests that external noise adds to the internal neural noise in the brain which increases the signal-to-noise ratio through stochastic resonance, and can either enhance or attenuate cognitive performance, depending on individuals’ attentiveness level. Both hypotheses were partially supported, with the reaction times decreasing in the WN and tDCS conditions for the ‘low attentiveness’ group but increasing for the ‘high attentiveness’ group, relative to the nonoise condition. However, no difference was found in accuracy.