According to Linda Rodriguez McRobbie, boredom may be "the evolutionary cousin to disgust":
In [Dr. Peter] Toohey’s Boredom: A Living History, the author notes that when writers as far back as Seneca talk about boredom, they often describe it was a kind of nausea or sickness. The title of famous 20th century existentialist writer Jean-Paul Sartre’s novel about existential boredom was, after all, Nausea. Even now, if someone is bored of something, they’re "sick of it" or "fed up". So if disgust is a mechanism by which humans avoid harmful things, then boredom is an evolutionary response to harmful social situations or even their own descent into depression.
"Emotions are there to help us react to, register and regulate our response to stimulus from our environment," he says. Boredom, therefore, can be a kind of early warning system. "We don’t usually take it as a warning – but children do, they badger you to get you out of the situation."