A new study suggests that spontaneous mind wandering—an unintentional drift of attention away from a task—predicts distinct aspects of ADHD symptoms in adults, indicating two separate mechanisms by which off-task thoughts may influence attention. The research, published in the Journal of Attention Disorders, identifies both a general tendency to experience spontaneous mind wandering in daily life and a momentary drop in performance during such episodes as linked to higher ADHD traits. The team is led by Takehiro Minamoto, an associate professor of psychology at Shimane University, with Takuma Hayashi and Md Abdullah Al-Mamun among the co-authors.
ADHD is a neurodevelopmental condition characterised by patterns of inattention, hyperactivity, and impulsive behaviour that disrupt daily functioning. A key area of inquiry for researchers is the brain’s default mode network, which tends to be active during rest or internal thought and typically quietens when a person concentrates on outward tasks. Mind wandering is now recognised as multidimensional, comprising deliberate, intentional shifts of thought, and spontaneous, intrusive, unintentional drifts that can disrupt ongoing tasks.
The researchers recruited 67 university students, applying self-report measures in the days leading up to the main experiment to gauge ADHD symptoms and tendencies for both deliberate and spontaneous mind wandering in daily life. They also completed a working memory test to account for general cognitive ability before taking part in the main session.
In the main session, participants performed a demanding counting Stroop task across 1,152 trials. They viewed groups of Japanese words representing numbers, with the text’s meaning often mismatching the actual quantity. Participants had to press the key corresponding to the number of words, ignoring the text, and the correct response key changed with every trial to deter guessing or motor habituation.
Crucially, the researchers paused the task 40 times at random intervals to probe the participants’ momentary attention, asking them to classify whether they were fully focused, engaging in deliberate mind wandering, experiencing spontaneous mind wandering, or dealing with other distractions at that instant.
The study found deliberate mind wandering occurred more frequently than spontaneous mind wandering, but spontaneous mind wandering had a significantly larger impact on performance. During spontaneous episodes, participants showed lower accuracy, slower responses, and greater variability in reaction times than during deliberate mind wandering, indicating a distinct behavioural penalty for unintentional off-task thoughts.
When examining ADHD traits, two independent predictors emerged. First, higher self-reported spontaneous mind wandering in daily life correlated with higher ADHD symptom scores. Second, poorer accuracy specifically during spontaneous mind wandering episodes on the counting task also correlated with higher ADHD scores. By contrast, neither deliberate mind wandering nor accuracy during deliberate mind wandering predicted ADHD symptoms.
The researchers propose that these findings reflect two separate forms of cognitive interference. The first is macroscopic, a persistent tendency for task-irrelevant thoughts to interfere with attention and self-regulation in everyday life. The second is microscopic, a momentary disruption in the ability to switch mental states and maintain focused attention during a task.
“Our findings suggest that spontaneous mind wandering may contribute to ADHD symptoms through at least two distinct mechanisms,” Minamoto noted. “One appears to reflect a persistent tendency for task-unrelated thoughts to interfere with attention and self-regulation, while the other reflects momentary disruptions in the ability to switch between mental states and maintain focus.”
He added: “This highlights that attentional difficulties in ADHD may not arise from a single underlying process, but from multiple forms of cognitive interference that affect everyday functioning.”
The study aligns with previous PsyPost reporting that mind wandering disrupts attention in children with ADHD, and with a 2024 study linking excessive mind wandering to ADHD symptoms in adults, though the current work relies on adult self-reports and real-time task performance rather than classroom observations.
There are limitations to note. The sample consisted entirely of university students, none of whom carried a formal ADHD diagnosis, so generalising to clinically diagnosed populations should be done cautiously. The counting Stroop task’s motor demands—moving between keys that varied in distance—may have influenced reaction times, potentially masking deeper relations between mind wandering and processing speed. As the study captured data at a single time point, it cannot determine causality between spontaneous mind wandering and ADHD symptoms.
Minamoto said further research is needed to confirm the two proposed forms of interference and to explore their neural underpinnings. He suggested that future work could inform more targeted behavioural, cognitive, and pharmacological interventions to alleviate ADHD-related challenges.
The study, titled Behavioral and Self-Report Measures of Spontaneous Mind Wandering Predict Different Aspects of ADHD in Adults, was authored by Takehiro Minamoto, Takuma Hayashi, and Md Abdullah Al-Mamun.
