Why Do We Scream?

 by Sabiha Sabikunnaher

The Scream by Edvard Munch, 1893

A few days ago, I was contemplating life in silence when something plopped onto my table. I beheld the monstrosity, and screamed.

It was a ladybug.

This small insect was simply attempting to position itself on my pencil, with no ill intent towards me and living its peaceful life. So why did I scream? (Apart from the fact that bugs terrify me). This got me to wonder why I had bothered wasting energy in straining my vocal chords when clearly nothing was wrong. I am not the only one who has pondered this as even Edvard Munch had portrayed his interest in the question through his ambiguous painting, ‘The Scream’. 

Multiple studies have shown that the screams from mammals fall into 3 categories: alarm, aggression and fear. Surely we humans are the same as from the evolutionary aspect, we are just intelligent monkeys. But monkeys don’t scream on roller coasters or in excitement at finding a banana. Screaming could be considered as a parallel for why we cry - simply a vocalisation of an intense emotion as a reflex or involuntary action from the moment we are born.

Further research has shown that instead of 3, human screams can be separated into 3 groups: pain, anger, fear and the additions of pleasure, sadness and joy, which are only identifiable in the human species. This just shows that over the years through evolution, humans signal more emotional significance to periods of intense pleasure and joy rather than in reaction to threatening situations, showing the change in priority as different requirements are needed in the more complex social contexts in humans.

But why do we scream when scared, even if there is no danger? This is because the survival instincts from our ancestors are ingrained inside us, causing us to go into survival mode as we are more alert to potential threats. So yes, in order to keep ourselves safe, we make loud, unintelligible noises which help us focus and caution others, even if it is from a fruit fly rather than a mammoth. 

However, for us to initiate our attack against the ‘predator’, our scream has to start in the limbic system (in our brain) which includes the hippocampus and amygdala that process memory and emotion. It then passes to the cerebellum where the sound formation of the scream is finally created, causing signals to be sent to the spinal cord and relevant muscles needed to vocalise our yelps for the entire world to hear. This in turn could activate the flight or flight response as well as increasing our heart rate and blood pressure. Screaming certainly doesn’t sound fun.

As you can imagine, screaming in terror is not the only reason why we do it, as it can also help ease stress and let out repressed emotions. Why else would you yell whilst beating up your couch in frustration? The roughness of your howling also presents what type of scream it may be as it varies from 30 to 150 Hz unlike normal speech which modulates between 4 and 5 Hz. The huge variation in the sound gives us a sense as to how our brain perceives danger, showing that the louder the scream the higher the danger and therefore heightening the awareness for both screamer and listener to respond to their environment. Yes, this might not be a life-or-death situation but seeing your bed hair is a good enough reason to shriek.

Even if the circumstances aren’t alarming, positive screams can be seen as a way of socialising. If one person begins to scream at a concert, someone else starts, feeling the same kind of joy as everyone else through the screaming, somehow creating social bonds between people. This can be seen as a giant evolutionary change because being faced with threatening situations is becoming less common as it is unlikely to be charged at by a bull at any second but more common to go to theme parks or concerts. Unless you live in the jungle.

In other words, you might scream to express your pleasure or terror to keep yourself safe, or just to alert others what's going through your head right now. In my case, no one was there to save me from the ladybug, so I stared at it intensely until it crawled away.