"Baaa-beee Shark! Doo-doo-doo-doo-doo-doo, Baby Shark! Doo-doo-doo-doo-doo-doo, Baby Shark! Doo-doo-doo-doo-doo-doo, Baby SHARK!..." Just when you got that song out of your head, something triggers it again, and, doo-doo-doo-doo-doo-doo… Baby Shark comes floating right back.
It follows you everywhere—to the store, to the bathroom, to bed. When you wake up in the morning, it doesn't take much to trigger its return—especially if you're still tired. And no matter how hard you try to unhear it, it just won't spare you another verse.
All of this happens for a reason—we are wired to learn by repetition throughout our life.
It may make some of these refrains a bit sweeter to know that the part of the brain that helps your baby learn to talk is the same part at work when you get a song stuck in your head. Called the Language Acquisition Device (LAD), it is the theoretical section of the brain thought to account for children's instinctive ability to acquire and produce language. As adults, we retain these LADs to enable us to learn things like a musical instrument or a second language.
In the LAD part of the brain, input, or what is heard, is processed through vocalization and repetition, which turns it into output, or the process that lays down neural networks and commits information to memory. This is why as parents we naturally reinforce the sounds our baby makes with intonation (melody), exaggeration, and repetition, "often reacting to early vocalizations as if they were intended to communicate something, responding in ways that are thought to promote communicative development," according to Snow and Ferguson.
When you get a song stuck in your head, it's called Involuntary Musical Imagery (INMI). Just like when your baby sings and makes sounds and you echo them and add words to activate their LAD, INMI is your own LAD being stimulated, producing the output necessary to process information and store it as a memory as if you were learning something new like a second language, or in this case, the song repeating in your head.
Humans are the only species to have language and sing.
There is anthropological evidence that homo sapiens sang (non-linguistic vocalizations) before speaking, according to anthropologist Frank B. Livingstone in Current Anthropology. The evolutionary basis for how we are wired to acquire language can explain why both unique capabilities work in concert when it comes to the LAD.
Neurologists have discovered that music is processed in the same area of the brain as language. Based on this, researchers "have hypothesized that by engaging and stimulating the LAD, a song may act as an activator or strategy in the development of language," from infancy to adulthood. And in learning language, infant vocalizations resemble singing more than speech. So when we naturally adjust the way we speak and sing to infants and small children we are actually teaching them to speak.
In a study out of Western Washington University, it was found that if a song continued to play in someone's head immediately after listening to it, that song was likely to return as an intrusive song within the next 24 hours. Hello, Baby Shark.
Additionally, it was discovered that intrusive songs return during times of low cognitive activities that require less problem solving, thinking and reasoning (when the output can more likely be processed), like folding laundry or spacing out when you are overtired.
It was found that the opposite can happen, too. Overloading our brains with challenging activities, like grocery shopping with toddlers or actively trying to block a song out of your head, can increase the frequency of that intrusive song as well. This can be explained by the Ironic Process Theory, where attempts to suppress a thought actually can cause an increase in the frequency of that thought.
Consciously attempting not to think about something is a mental control strategy known as thought suppression. This strategy can be successful under certain conditions, but it often promotes an increase in the accessibility of the thought to our consciousness. In other words, this theory suggests that if you consciously try not to think about Baby Shark, by thinking about it, an unconscious, automatic search for the song ironically results in a failure to not not think about it, producing the very state of mind you least desire.
This happens especially during times of stress, distraction, time urgency, or other mental load (...um, parenting). And this can be extrapolated to other parts of your life, not just Baby Shark.
So, basically, your attempts to gain mental control may actually create the unwanted mental state you were trying to avoid. (Fun fact: this happens more to women than men.)