In Diary of a Cosmonaut: 211 Days in Space, Valentin Lebedev recorded his daily experiences during a record-breaking seven-month stint in space. Even as scientific experiments occupied his time, the monotony crept in; as he noted in his diary after only a week, “the drab routine has begun.” Boredom, it turns out, can affect anyone—including Soviet cosmonauts. Characterized by feelings of emptiness, frustration and apathy, it is widely recognized as a temporary emotional state that arises in response to tedium. 

For some, the result can be impulsive behaviors with negative consequences, such as gambling and drug abuse. Others may find themselves mindlessly scrolling through their apps in what has been dubbed “phone boredom.” Yet a growing number of psychologists are warning a...