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How Fear Works

2020-02-05, 20:28

It's dark out, and you're home alone. The house is quiet other than the sound of the show you're watching on TV. You see it and hear it at the same time: The front door is suddenly thrown against the door frame.
Your breathing speeds up. Your heart races. Your muscles tighten.A split second later, you know it's the wind. No one is trying to get into your home.For a split second, you were so afraid that you reacted as if your life were in danger, your body initiating the fight-or-flight response that is critical to any animal's survival. But really, there was no danger at all. What happened to cause such an intense reaction? What exactly is fear? In this article, we'll examine the psychological and physical properties of fear, find out what causes a fear response and look at some ways you can defeat it.What is Fear?Fear is a chain reaction in the brain that starts with a stressful stimulus and ends with the release of chemicals that cause a racing heart, fast breathing and energized muscles, among other things, also known as the fight-or-flight response. The stimulus could be a spider, a knife at your throat, an auditorium full of people waiting for you to speak or the sudden thud of your front door against the door frame.­ ­The brain is a profoundly complex organ. More than 100 billion nerve cells comprise an intricate network of communications that is the starting point of everything we sense, think and do. Some of these communications lead to conscious thought and action, while others produce autonomic responses. The fear response is almost entirely autonomic: We don't consciously trigger it or even know what's going on until it has run its course.Because cells in the brain are constantly transferring information and triggering responses, there are dozens of areas of the brain at least peripherally involved in fear. But research has discovered that certain parts of the brain play central roles in the process:
 
  • Thalamus - decides where to send incoming sensory data (from eyes, ears, mouth, skin)
  • Sensory cortex - interprets sensory data
  • Hippocampus - stores and retrieves conscious memories; processes sets of stimuli to establish context
  • Amygdala - decodes emotions; determines possible threat; stores fear memories
  • Hypothalamus - activates "fight or flight" response
T­he process of creating fear begins with a scary stimulus and ends with the fight-or-flight response. But there are at least two paths between the start and the end of the process. In the next section, we'll take a closer look at how fear is created.

Creating Fear

Creating fear is a process that takes place in the brain and is completely unconscious. Learn about the process of creating fear and the paths of fear.

 
Creating fear is a process that takes place in the brain and is completely unconscious. Learn about the process of creating fear and the paths of fear.
The process of creating fear takes place in the brain and is entirely unconscious. There are two paths involved in the fear response: The low road is quick and messy, while the high road takes more time and delivers a more precise interpretation of events. Both processes are happening simultaneously.The idea behind the low road is "take no chances." If the front door to your home is suddenly knocking against the frame, it could be the wind. It could also be a burglar trying to get in. It's far less dangerous to assume it's a burglar and have it turn out to be the wind than to assume it's the wind and have it turn out to be a burglar. The low road shoots first and asks questions later. The process looks like this:The door knocking against the door frame is the stimulus. As soon as you hear the sound and see the motion, your brain sends this sensory data to the thalamus. At this point, the thalamus doesn't know if the signals it's receiving are signs of danger or not, but since they might be, it forwards the information to the amygdala. The amygdala receives the neural impulses and takes action to protect you: It tells the hypothalamus to initiate the fight-or-flight response that could save your life if what you're seeing and hearing turns out to be an intruder.The high road is much more thoughtful. While the low road is initiating the fear response just in case, the high road is considering all of the options. Is it a burglar, or is it the wind? The long process looks like this:When your eyes and ears sense the sound and motion of the door, they relay this information to the thalamus. The thalamus sends this information to the sensory cortex, where it is interpreted for meaning. The sensory cortex determines that there is more than one possible interpretation of the data and passes it along to the hippocampus to establish context. The hippocampus asks questions like, "Have I seen this particular stimulus before? If so, what did it mean that time? What other things are going on that might give me clues as to whether this is a burglar or a wind storm?" The hippocampus might pick up on other data being relayed through the high road, like the tapping of branches against a window, a muffled howling sound outside and the clatter of patio furniture flying about. Taking into account this other information, the hippocampus determines that the door action is most likely the result of wind. It sends a message to the amygdala that there is no danger, and the amygdala in turn tells the hypothalamus to shut off the fight-or-flight response.The sensory data regarding the door -- the stimulus -- is following both paths at the same time. But the high road takes longer than the low road. That's why you have a moment or two of terror before you calm down.Regardless of which path we're talking about, all roads lead to the hypothalamus. This portion of the brain controls the ancient survival reaction called the fight-or-flight response. In the next section, we'll take a closer look at the fight-or-flight response.

Fight or Flight

 
To produce the fight-or-flight response, the hypothalamus activates two systems: the sympathetic nervous system and the adrenal-cortical system. The sympathetic nervous system uses nerve pathways to initiate reactions in the body, and the adrenal-cortical system uses the bloodstream. The combined effects of these two systems are the fight-or-flight response.When the hypothalamus tells the sympathetic nervous system to kick into gear, the overall effect is that the body speeds up, tenses up and becomes generally very alert. If there's a burglar at the door, you're going to have to take action -- and fast. The sympathetic nervous system sends out impulses to glands and smooth muscles and tells the adrenal medulla to release epinephrine (adrenaline) and norepinephrine (noradrenaline) into the bloodstream. These "stress hormones" cause several changes in the body, including an increase in heart rate and blood pressure.At the same time, the hypothalamus releases corticotropin-releasing factor (CRF) into the pituitary gland, activating the adrenal-cortical system. The pituitary gland (a major endocrine gland) secretes the hormone ACTH (adrenocorticotropic hormone). ACTH moves through the bloodstream and ultimately arrives at the adrenal cortex, where it activates the release of approximately 30 different hormones that get the body prepared to deal with a threat.The sudden flood of epinephrine, norepinephrine and dozens of other hormones causes changes in the body that include:
  • heart rate and blood pressure increase
  • pupils dilate to take in as much light as possible
  • veins in skin constrict to send more blood to major muscle groups (responsible for the "chill" sometimes associated with fear -- less blood in the skin to keep it warm)
  • blood-glucose level increases
  • muscles tense up, energized by adrenaline and glucose (responsible for goose bumps -- when tiny muscles attached to each hair on surface of skin tense up, the hairs are forced upright, pulling skin with them)
  • smooth muscle relaxes in order to allow more oxygen into the lungs
  • nonessential systems (like digestion and immune system) shut down to allow more energy for emergency functions
  • trouble focusing on small tasks (brain is directed to focus only on big picture in order to determine where threat is coming from)
All of these physical responses are intended to help you survive a dangerous situation by preparing you to either run for your life or fight for your life (thus the term "fight or flight"). Fear -- and the fight-or-flight response in particular -- is an instinct that every animal possesses.

How Fear Works

Why Do We Fear?

If we couldn't be afraid, we wouldn't survive for long. We'd be walking into oncoming traffic, stepping off of rooftops and carelessly handling poisonous snakes. We'd be hanging out with people who have tuberculosis. In humans and in all animals, the purpose of fear is to promote survival. In the course of human evolution, the people who feared the right things survived to pass on their genes. In passing on their genes, the trait of fear and the response to it were selected as beneficial to the race.

During the 19th-century debate surrounding evolution, the "face of fear" -- that wide-eyed, gaping grimace that often accompanies sheer terror -- became a talking point. Why do people make that face when they're terrified? Some said God had given people a way to let others know they were afraid even if they didn't speak the same language. Charles Darwin said it was a result of the instinctive tightening of muscles triggered by an evolved response to fear. To prove his point, he went to the reptile house at the London Zoological Gardens. Trying to remain perfectly calm, he stood as close to the glass as possible while a puff adder lunged toward him on the other side. Every time it happened, he grimaced and jumped back. In his diary, he writes, "My will and reason were powerless against the imagination of a danger which had never been experienced." He concluded that the entire fear response is an ancient instinct that has been untouched by the nuances of modern civilization [ref].Most of us are no longer fighting (or running) for our lives in the wild, but fear is far from an outdated instinct. It serves the same purpose today as it did when we might run into a lion while carrying water back from the river. Only now, we're carrying a wallet and walking down city streets. The decision not to take that shortcut through the deserted alley at midnight is based on a rational fear that promotes survival. Only the stimuli have changed -- we're in as much danger today as we were hundreds of years ago, and our fear serves to protect us now as it did then.Darwin had never experienced the bite of a poisonous snake, and yet he reacted to it as if his life were in danger. Most of us have never been anywhere near The Plague, but our heart will skip a beat at the sight of a rat. For humans, there are other factors involved in fear beyond instinct. Human beings have the sometimes unfortunate gift of anticipation, and we anticipate terrible things that might happen -- things we have heard about, read about or seen on TV. Most of us have never experienced a plane crash, but that doesn't stop us from sitting on a plane with white-knuckle grips on the armrests. Anticipating a fearful stimulus can provoke the same response as actually experiencing it. This also is an evolutionary benefit: Those humans who felt rain, anticipated lightning and remained in the cave until the storm passed had a better chance of not getting struck with thousands of volts of electricity. We'll look at ways in which we are conditioned to fear in the next section.
FEAR AND EXCITEMENTIf you enjoy horror movies, you know that fear can be exciting. Many people enjoy being afraid -- the arousal that comes with the fight-or-flight response can be pleasurable and can even mimic sexual arousal. It's no wonder so many people go to see scary movies and ride roller coasters on dates.There is actual scientific evidence that supports the fear-attraction connection. Psychologist Arthur Aron conducted a study using the very common fear of heights. Aron had one group of men walk across a 450-foot-long, unstable-feeling bridge suspended over a 230-foot drop; he had another group of men walk across a perfectly stable-feeling bridge over the same height. At the end of each bridge, the men met Aron's very beautiful female assistant. She asked each subject a set of questions related to an imaginary study and then gave him her phone number in case he wanted more information. Of the 33 men who'd walked across the stable bridge, two called the assistant. Of the 33 who'd walked across the swaying bridge, nine called. Aron concluded that the state of fear encourages sexual attraction.

Fear Conditioning

Fear conditioning is why some people are afraid of rats and dogs.
 
Fear conditioning is why some people are afraid of rats and dogs.
CHINA PHOTOS/GETTY IMAGES
The circuitry of the fear response may have been honed by evolution, but there is also another side to fear: conditioning. Conditioning is why some people fear dogs as if they were fire-breathing monsters, while others consider them part of the family.In the 1920s, in what is probably not one of psychology's finest moments, American psychologist John Watson taught an infant to fear white rats. "Little Albert" had no fear of the laboratory's test animals. He showed joy at the sight of the white rats especially and always reached out for them. Watson and his assistant taught Albert to be terrified of white rats. They used Pavlovian (classical) conditioning, pairing a neutral stimulus (the rat) with a negative effect. Whenever Albert reached for one of the rats, they created a terrifyingly loud noise right behind the 11-month-old child. Not only did Albert very quickly learn to fear the white rats, crying and moving away whenever he saw one, but he also started to cry in the presence of other furry animals and a Santa Claus mask with a white beard.
Like Little Albert's fear of white rats, a person's fear of dogs is most likely a conditioned response. Perhaps he was bitten by a dog when he was three years old. Twenty years later, the person's brain (the amygdala in particular) still associates the sight of a dog with the pain of a bite. We'll take a closer look at some common fears in the next section
 
Common Fears
A Gallup Poll conducted in 2005 reveals the most common fears of teenagers in the United States. The top 10 list goes like this:


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Duisen361 Акан
2020-03-03. 00:16

О чем же интересно пост.))