was somewhat counteracted by people's tendency to mind-wander to happy topics, but unhappy mind-wandering was more likely to be rated as more unpleasant than other activities. The authors note that unhappy moods can also cause mind-wandering, but the time-lags between mind-wandering and mood suggests that mind-wandering itself can also lead to negative moods. Furthermore, research suggests that regardless of working memory capacity, subjects participating in mind-wandering experiments report more mind-wandering when bored, stressed, or unhappy. Executive functions Executive functions (EFs) are cognitive processes that make a person pay attention or concentrate on a task. Three executive functions that relate to memory are inhibiting, updating and shifting. Inhibiting controls a person's attention and thoughts when distractions are abundant. Updating reviews old information and replaces it with new information in the working memory. Shifting controls the ability to go between multiple tasks. All three EFs have a relationship to mind-wandering. Executive functions have roles in attention problems, attention control, thought control, and working memory capacity. Attention problems relate to behavioral problems such as inattention, impulsivity and hyperactivity. These behaviors make staying on task difficult leading to more mind-wandering. Higher inhibiting and updating abilities correlates to lower levels of attention problems in adolescence. The inhibiting executive function controls attention and thought. The failure of cognitive inhibition is a direct cause of mind-wandering. Mind-wandering is also connected to working memory capacity (WMC). People with higher WMC mind-wander less on high concentration tasks no matter their boredom levels. People with low WMC are better at staying on task for low concentration tasks, but once the task increases in difficulty they had a hard time keeping their thoughts focused on task. Updating takes place in the working memory, therefore those with low WMC have a lower updating executive function ability. That means a low performing updating executive function can be an indicator of high mind-wandering. Working memory relies on executive functions, with mind-wandering as an indicator of their failure. Task-unrelated thoughts (TUTs) are empirical behavioral manifestations of mind-wandering in a person. The longer a task is performed the more TUTs reported. Mind-wandering is an indication of an executive control failure that is characterized by TUTs. Metacognition serves to correct the wandering mind, suppressing spontaneous thoughts and bringing attention back to more "worthwhile" tasks. Fidgeting Paul Seli and colleagues have shown that spontaneous mind-wandering is associated with increased fidgeting; by contrast, interest, attention and visual engagement lead