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What is Fear ?
Judging what you like or dislike allows you to enjoy life. In addition, knowing what you should fear, and quickly recognizing the biological changes in your body that indicate fear, could save your life. This critical task is largely handled by a small almond-shaped structure, the amygdala, which lies deep within the bottom of the brain, not far from your ears. The amygdala receives information from many brain regions, your internal organs, and external sensory systems, such as your eyes and ears. The amygdala integrates this information with various internal drives, such as whether you are hungry or thirsty or in pain; it then assigns a level of emotional significance to whatever is going on. For example, when the amygdala becomes aware that you are alone and hearing unfamiliar sounds in the dark, it initiates a fear response, such as panic or anxiety. It then activates the appropriate body systems, the release of hormones, and specific behaviors to respond to the (real or imagined) threat. The amygdala also is activated by sensory stimuli that seem ambiguous or unfamiliar to us, such as unfamiliar sounds or people. In response to ambiguous or unfamiliar stimuli, we become vigilant and pay closer attention to what is happening in our immediate environment. If you were a dog, your ears would perk up. Your amygdala gathers as much sensory information as possible, compares it to what you already know, and then instructs other brain regions to respond.
Almost without fail, and regardless of the nature of the information gathered by your vigilant brain, the amygdala usually comes to the same conclusion: be afraid. If a sensory event, such as a sight or sound or taste, is unfamiliar; your limbic system almost always assumes that the situation is potentially dangerous and should be treated as such. If everything
is assumed to be dangerous until proven otherwise, you are much more likely to survive the experience and pass on your be-fearful-first genes. Thus, humans fear everything that is unfamiliar or not-like-me: we fear unfamiliar dogs, people who look or dress differently, unfamiliar places, unfamiliar odors, things that go bump in the night, people who stare at us for too long, heights, enclosed small spaces, dark alleys, unknown people who follow us, etc. You get the idea. We all have witnessed the consequences of fear: we hide behind closed doors, we hide in protected or gated communities, we keep a loaded gun by every door and under the pillow, we hire bodyguards, we install security systems, we build walls. Brains evolved to perform one primary function: survival of the individual and the species; fear plays a critical role in survival. Unfortunately, your fear-inducing amygdala occasionally overreacts to trivial or harmless stimuli. Sometimes the amygdala induces behaviors that may get a person mentioned on the evening news.
Consider the following scenario: You are walking in an unfamiliar wooded area and you are aware of recent reports that snakes have been spotted along your current route. Then, without warning, you spot something brown, round, and coiled up on the ground next to a fallen tree. Your flight-or-fight response to this potential threat is activated immediately, quickly increasing your heart rate, respiration, and blood pressure; then, you realize that it is only a coil of discarded rope. Was your physiological response reasonable and appropriate? Yes, it was, because it prepared you to escape or defend yourself from a perceived danger. Your physiological response was so fast that it preceded recognition of the actual stimulus, the rope, due to the fact that your amygdala appears to receive partially processed sensory information before the more complex parts of your brain have had a chance to identify the true nature of the threat. Your brain evolved to help you survive to pass on your genes to the next generation. The best way to achieve this goal is to induce a response immediately to
imagined threats regardless of whether that response is appropriate or not. Whether you are walking down a dark alley or are in a landscape full of snakes does not make any difference to your brain; you need to prepare yourself for fight or flight to defend your be-fearful-first genes so that you can pass those be-fearful-first genes along to your offspring.
By now you have clearly gotten the point that being frightened of everything all of the time is a safe and effective way to maintain your species. Unfortunately, it is also quite stressful, and chronic stress ultimately will have negative consequences upon your health. The brain, due to the impact of evolution, does not concern itself with the long-term effects of chronic stress on the body because these negative consequences usually appear long after you have finished reproducing and passing on your be-fearful-first genes to the next generation.
Due to its control over your emotional response, the amygdala plays a critical role in the decision-making processes in your brain. In order to achieve this goal, the amygdala influences the function of many other brain regions. It activates the frontal lobes of your brain to increase your vigilance to potential threats. The amygdala also controls how your brain processes sensory inputs that are associated with emotional experiences. This is an extremely important function because it determines whether you will remember the details of fearful events. For example, mugging victims tend to distort the details of the tragic event by “remembering” that the mugger was bigger and uglier, the gun was bigger, the alley was darker, etc. The brain is not an accurate recording device; the influence of the amygdala makes memories more interesting or frightening than the events truly were. The influence of the amygdala, however, also makes it less likely that you will walk down that alley alone again. Your amygdala has succeeded again and your be-fearful-first genes live to breed another day!
The amygdala also becomes quite active when other people are looking at us. This response underlies why public speaking is usually rated as people’s number-one fear; even more feared than heights, deep water, death, bugs, loneliness, and darkness. Neurons in the amygdala pay attention to the eyes of other people in order to inform you whether someone is staring at you. Staring at one’s prey is a challenging action that is often a prelude to an attack. If someone in a crowded room, even if it was only a little girl holding her doll, started staring at you, how would that make you feel? She is following you, keeping her eyes trained on your every move; even her doll’s eyes now seem focused on you. What does she want from you? Why is she following you? Feeling threatened yet? Yes, indeed! We all would respond with fear to a similar situation, no matter how innocent the “attacker” might seem.
Children with autism do not respond to staring; magnetic resonance imaging (MRI) scanning studies of their amygdalae indicate that these children primarily pay attention to the mouths of other people and, therefore, miss critical social cues. The amygdala in older people is less responsive to social cues, threatening or not, than it is in younger people. Why? Possibly because as we get older and experience numerous and varied emotional and fearful events, our frontal lobes gain more control over how the amygdala responds to incoming sensory information. Studies have shown that the frontal lobe is responsible for turning off the amygdala. Indeed, humans with a thicker frontal cortex (specifically, the bottom middle of the brain) have a greater ability to reduce activation of their amygdala that is prompted by strongly emotional stimuli. You might remember the television show Star Trek and the planet of Vulcans who were always in complete control of their emotions; possibly the Vulcans had big frontal lobes.
Studies of brains from preterm babies have shown that the amygdala is wired up to the rest of the brain prior to birth and is, therefore, capable of helping the brain store strong, usually fearful, emotional memories. This might explain why some adults have inexplicable fears. Possibly, at this very early stage of brain development, the amygdala was able to record a negative memory while the hippocampus was still unable to form a memory of the event associated with the unpleasant experience.
Almost without fail, and regardless of the nature of the information gathered by your vigilant brain, the amygdala usually comes to the same conclusion: be afraid. If a sensory event, such as a sight or sound or taste, is unfamiliar; your limbic system almost always assumes that the situation is potentially dangerous and should be treated as such. If everything
is assumed to be dangerous until proven otherwise, you are much more likely to survive the experience and pass on your be-fearful-first genes. Thus, humans fear everything that is unfamiliar or not-like-me: we fear unfamiliar dogs, people who look or dress differently, unfamiliar places, unfamiliar odors, things that go bump in the night, people who stare at us for too long, heights, enclosed small spaces, dark alleys, unknown people who follow us, etc. You get the idea. We all have witnessed the consequences of fear: we hide behind closed doors, we hide in protected or gated communities, we keep a loaded gun by every door and under the pillow, we hire bodyguards, we install security systems, we build walls. Brains evolved to perform one primary function: survival of the individual and the species; fear plays a critical role in survival. Unfortunately, your fear-inducing amygdala occasionally overreacts to trivial or harmless stimuli. Sometimes the amygdala induces behaviors that may get a person mentioned on the evening news.
Consider the following scenario: You are walking in an unfamiliar wooded area and you are aware of recent reports that snakes have been spotted along your current route. Then, without warning, you spot something brown, round, and coiled up on the ground next to a fallen tree. Your flight-or-fight response to this potential threat is activated immediately, quickly increasing your heart rate, respiration, and blood pressure; then, you realize that it is only a coil of discarded rope. Was your physiological response reasonable and appropriate? Yes, it was, because it prepared you to escape or defend yourself from a perceived danger. Your physiological response was so fast that it preceded recognition of the actual stimulus, the rope, due to the fact that your amygdala appears to receive partially processed sensory information before the more complex parts of your brain have had a chance to identify the true nature of the threat. Your brain evolved to help you survive to pass on your genes to the next generation. The best way to achieve this goal is to induce a response immediately to
imagined threats regardless of whether that response is appropriate or not. Whether you are walking down a dark alley or are in a landscape full of snakes does not make any difference to your brain; you need to prepare yourself for fight or flight to defend your be-fearful-first genes so that you can pass those be-fearful-first genes along to your offspring.
By now you have clearly gotten the point that being frightened of everything all of the time is a safe and effective way to maintain your species. Unfortunately, it is also quite stressful, and chronic stress ultimately will have negative consequences upon your health. The brain, due to the impact of evolution, does not concern itself with the long-term effects of chronic stress on the body because these negative consequences usually appear long after you have finished reproducing and passing on your be-fearful-first genes to the next generation.
Due to its control over your emotional response, the amygdala plays a critical role in the decision-making processes in your brain. In order to achieve this goal, the amygdala influences the function of many other brain regions. It activates the frontal lobes of your brain to increase your vigilance to potential threats. The amygdala also controls how your brain processes sensory inputs that are associated with emotional experiences. This is an extremely important function because it determines whether you will remember the details of fearful events. For example, mugging victims tend to distort the details of the tragic event by “remembering” that the mugger was bigger and uglier, the gun was bigger, the alley was darker, etc. The brain is not an accurate recording device; the influence of the amygdala makes memories more interesting or frightening than the events truly were. The influence of the amygdala, however, also makes it less likely that you will walk down that alley alone again. Your amygdala has succeeded again and your be-fearful-first genes live to breed another day!
The amygdala also becomes quite active when other people are looking at us. This response underlies why public speaking is usually rated as people’s number-one fear; even more feared than heights, deep water, death, bugs, loneliness, and darkness. Neurons in the amygdala pay attention to the eyes of other people in order to inform you whether someone is staring at you. Staring at one’s prey is a challenging action that is often a prelude to an attack. If someone in a crowded room, even if it was only a little girl holding her doll, started staring at you, how would that make you feel? She is following you, keeping her eyes trained on your every move; even her doll’s eyes now seem focused on you. What does she want from you? Why is she following you? Feeling threatened yet? Yes, indeed! We all would respond with fear to a similar situation, no matter how innocent the “attacker” might seem.
Children with autism do not respond to staring; magnetic resonance imaging (MRI) scanning studies of their amygdalae indicate that these children primarily pay attention to the mouths of other people and, therefore, miss critical social cues. The amygdala in older people is less responsive to social cues, threatening or not, than it is in younger people. Why? Possibly because as we get older and experience numerous and varied emotional and fearful events, our frontal lobes gain more control over how the amygdala responds to incoming sensory information. Studies have shown that the frontal lobe is responsible for turning off the amygdala. Indeed, humans with a thicker frontal cortex (specifically, the bottom middle of the brain) have a greater ability to reduce activation of their amygdala that is prompted by strongly emotional stimuli. You might remember the television show Star Trek and the planet of Vulcans who were always in complete control of their emotions; possibly the Vulcans had big frontal lobes.
Studies of brains from preterm babies have shown that the amygdala is wired up to the rest of the brain prior to birth and is, therefore, capable of helping the brain store strong, usually fearful, emotional memories. This might explain why some adults have inexplicable fears. Possibly, at this very early stage of brain development, the amygdala was able to record a negative memory while the hippocampus was still unable to form a memory of the event associated with the unpleasant experience.
