Randomness as a behavioral marker of attentional control during the attention training technique and its neural correlates.

Background: The Attention Training Technique (ATT) is a core intervention of metacognitive therapy (MCT) effective in reducing repetitive negative thinking by engaging the lateral prefrontal cortex (PFC). The current study tests whether a parallel random number generation (RNG) task can serve as a behavioral marker of attentional engagement. Methods: We conducted two studies using the fMRI-adapted ATT paradigm combined with a parallel RNG task. In the behavioral study (N = 36), we compared two task versions with short (21 presses) versus long (45 presses) trials. In the fMRI study (N = 42), the ATT paradigm was performed with either parallel RNG or a motor control task. Markers of randomness (i.e., Redundancy, Repetition Gap, and Coupon scores) were compared between ATT conditions. Trait AC was measured using the Attentional Control Scale (ACS). Results: Randomness was reduced during ATT compared to control trials in both studies ( Conclusions: These findings establish RNG as a feasible and sensitive behavioral marker of ATT engagement and offer the opportunity to link behavioral performance during ATT to individual differences in AC. However, dual-task demands limit the use of RNG as a behavioral marker, particularly in fMRI which calls for alternative, behavior-independent measures of attentional effort.