Today’s Wonder of the Day was inspired by Bri. Bri Wonders, “What does your body do when you're scared?” Thanks for WONDERing with us, Bri!

Imagine you’ve woken up in the middle of the night. You look at the clock: 3 a.m. You throw back the covers and sit up. A glass of water may help you get back to sleep. You head down the hallway to the kitchen. That’s when a sight stops you dead in your tracks.

What is that? Down the hall, in front of the window, is a dark figure. You can see its outline illuminated by the streetlight outside. It looks like a tall… person? Maybe. But something about it seems inhuman. And it’s so still. Does it see you?

Your heart races. Your palms sweat. There’s a knot in your stomach, and you feel tense all over. You move toward the light switch as your knees go weak. Your breath quickens as you summon up all your bravery. You flip the light on to see…

The coat rack! You forgot that a family member moved it in front of the window a few days ago. Whew! What a relief. There’s nothing to worry about, and you can drink your glass of water and get back to bed.

But that’s when you start to WONDER. What just happened? Why did your body respond the way it did? How do your heart, hands, lungs, and knees know when you’re afraid?

People have studied the science behind fear for many years. Experts have found that humans have fear to thank for helping them survive as a species for thousands of years. How’s that? Well, in many cases, fear protects people. 

When you see a snake slithering through the grass, you probably head in the other direction. When you near the edge of an elevated surface, you don’t get close enough to fall. These actions are triggered by fear, and they stop you from getting hurt. That snake could be venomous, and you could fall off that edge. Thanks to fear, you avoid both.

And your body’s reaction to fear protects you, too. It all starts in the brain. When you see something that scares you, a part of your brain called the amygdala is alerted. The amygdala then communicates the fear to other parts of the brain.

Have you ever heard that all people have a fight-or-flight reaction to fear? That reaction is triggered by another part of the brain—the hippocampus. The hippocampus and prefrontal cortex work together to decide whether there is a real threat to your safety. Then, the hippocampus tells you how to respond.

Once it interprets your fear, your brain sends out messages to the rest of your body. It tells some of your organs—like your heart, lungs, and adrenal glands—to speed up. This helps you prepare for your fight-or-flight response. Whether you run (flight) or engage with the threat (fight), you’ll need those organs working in overdrive. The brain also tells your pupils to dilate so that you can see better.

At the same time, your brain tells other parts of your body to slow down. For example, when you’re afraid, your digestive organs slow their work. This helps your body preserve energy for the processes that are more essential for your safety.

Of course, you feel all these processes in the faster beating of your heart and breathing of your lungs. Most people are familiar with the feeling of fear. But seeing that shadowy figure in the middle of the night is a much different feeling than going into a haunted house on Halloween. Both of these events trigger fear, but one is fun and the other definitely isn’t. So why is it that people like to be scared sometimes?

It all has to do with the response of your hippocampus and prefrontal cortex. When they’re working to decide whether a threat is real, they consider two things—emotion and context. If you feel fear (emotion) in a haunted house (context), your brain will know that the threat isn’t real. It knows that you chose to go into the haunted house and that none of the things you’re seeing are really going to hurt you. So, even though you might feel fear, your brain knows that you’re not in real danger.

Some people definitely like being scared more than others. In fact, many people would refuse to go into a haunted house, even though they know it’s not a real threat. And that’s okay! All people respond to fear in different ways. However your body responds to being afraid, remember it’s just trying to protect you.

Standards: NGSS.LS1.A, NGSS.LS1.D, CCRA.R.4, CCRA.L.3, CCRA.L.6, CCRA.R.1, CCRA.R.2, CCRA.W.2, CCRA.W.9, CCRA.L.1, CCRA.L.2, CCRA.R.10, CCRA.SL.1

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