Everything all at Once: Enhanced Sensitivity and Altered Information Processing of Internet-Addiction Individuals in Numerical Stroop ERP Experiment

Internet has reshaped our way of thinking and doing. Internet addiction (IA) is defined as the problematic patterns of Internet use that may result from dysfunction of inhibitory functions and compromised attention regulation. However, in our previous study using numerical Stroop task, we found no worse accuracy and even a tendency of faster reaction times (RT) for the IA compared to normal control participants (NC). To further investigate the underlying neural dynamics contributing to this faster response, we conducted single-trial analysis on ERPs by sorting the trials into 3 RT bins: fast, medium, and slow. In slow trials, only IA displayed enhanced N100 for congruent and incongruent conditions, indicating early perception of the embedded physical size. Also, IA displayed a facilitation effect (Congruent-Neutral) on early and late LPC. However, in fast RT trials, IA showed a similar pattern of facilitation (on N200 and early LPC) and interference (Incongruent-Neutral, on N450 and late LPC) effect to that of NC. These findings demonstrated that IA were capable of alike processing as NC, yet exhibited enhanced sensitivity on physical though goal-irrelevant information at the early stage processing. The heightened attention to the early sensory information can be beneficial to expedite the responses overall. Despite reported cognitive deficits associated with IA, our study reveals alternation in information processing mechanisms, specifically in attention regulation and allocation of cognitive resources due to habitual multitasking and excessive online content consumption.