Why Are Nails On A Chalkboard So Annoying? Here's The Science Behind Irritating Sounds — VIDEO

What horrible sounds do you have a visceral reaction to? Nails on a chalkboard? Styrofoam squeaks? Turns out, there's a science behind why certain sounds are so irritating to humans, and the implications are way weirder than you'd expect.

Hank Green, brother of author John Green and host of the YouTube series SciShow, recently took on the topic "Why do some noises make you cringe?" Sure, there are plenty of subjectively unpleasant sounds — Donald Trump's voice for example — but there are a handful of noises that pretty much everyone can agree are horrible, right?

According to science, yep. A study in 1986 asked 24 adults to rank 16 sounds based on their "unpleasantness," which honestly sounds like a nightmarish study to participate in, but whatever. The sounds that subjects routinely ranked as the worst, like a fork scraping against a plate, shared a frequency range between 2,000 and 5,000 Hz. Subsequent studies have found that humans do in fact have a subconscious, physical reaction to certain sounds within this frequency range, with measurable changes in skin conductivity (a sign of stress).

But why these particular sounds? Well, scientists have a few theories:

1. Vestigial Sensitivity to Sounds of Distress

Some scientists wonder if our hatred of these sounds is evolutionarily based. Baby screams fall within this frequency, and it makes sense that humans are hard-wired to react to those (because how else are we going to continue our species?). In addition, scientists tested the sounds of "seriously distressed" monkeys, and found that these, too, fall within the frequency range danger zone. However, this theory is kind of difficult to actually, like, prove.

2. We're Triggered from Past Experiences

I mean, yeah, imagining my nails scraping against a chalkboard is making me massively uncomfortable right now, so. Thanks, Hank.

But OK, even if the sounds are not evolutionarily-based, scientists are still baffled as to why we have such a visceral response to them. A 2012 study from Newcastle University subjected 16 people to 74 sounds. Here are the top 10 worst sounds. Sorry in advance for any cringing you may do:

In monitoring peoples' brains during this study, scientists found that, in response to irritating sounds, the auditory cortex, which processes sound, and the amygdala, which is involved in emotions like anger and fear, both lit up.

It's possible that the amygdala actually influences the auditory cortex's response, making us experience more sensitivity and discomfort when faced with an "irritating" sound.

Weirdly fascinating, right? Check out the full video below:

Images: IDS Photography/Stocksy; SciShow/YouTube (5)