Читать книгу The Courageous Classroom - Jed Dearybury - Страница 13
Fear Keeps Us Alive
ОглавлениеAvoiding being eaten by predators is an early evolutionary task of animals and humans. Basic survival is one of the most cogent demands in the ecosystem. The neurophysiology of both our body and brain for survival has been engineered and adapted over time for one reason … staying alive. Charles Darwin, a biologist and geologist known for his writings about our human struggle for existence through natural selection, said, “Organisms unable to adapt to the demands of their environment will fail to pass on their genes and fall as casualties in the ‘war on nature’” (Darwin 1871).
Human beings are tasked with being smarter than their predators while managing the demands of eating, sleeping, procreating, and avoiding being resource depleted. Lines are drawn as we constantly monitor whether we can safely eat, live, and sleep. Imagine your brain on a Zoom conference call that never stops: there's cross talk and background noise, distractions abound, feelings arise – anxiety, excitement, boredom, anger, frustration – you want to exit, but your brain never hits “leave the meeting.” Our brain has the ability to uniquely focus, allowing us to respond to different environments, and circumstances whether they are non-threatening or life-endangering, 24/7.
Fear can result from the presence of a real threat that may be in your face or miles away. The level of danger that you feel is anchored in how close it is and how great the potential is for it to get closer. If you have had the experience of listening to weather forecasts that start as a threat, advance to a warning, and leap to blaring sirens instructing you to take immediate cover, then chances are you have experienced the physiological symptoms of fear: increased heart rate, rapid breathing, sweaty hands, and a sinking feeling in your gut. At the same time, your brain is processing the depth of danger and sending biochemical messages throughout your body.
In that same situation of an ominous weather forecast, anxiety may present when you hear the initial forecast, and will depend on both your experience with bad storms, or watching others' bad experiences with storms, or simply having a personality that worries about natural disasters. Anxiety can occur with remote, unusual, or abstract triggers that usually aren't related to a direct threat. Anxiety can occur in conditions that are safe, but lead to what if thoughts triggering brain and body unrest.
Both anxiety and fear can lead to avoidance behavior, and involve emotions that can invade our sense of well-being. It's important to understand that even with fear and anxiety we have time to think, assess the threat, determine if we need to run or fight or relax and stay put. The key point here is when you feel fearful, notice your anxiety … take a breath. When our brain perceives a threat, it actively will work for our safety and survival.
To survive, animals and humans must know how to recognize and respond to a threat. Our preferred state is to be in a safe, secure place. When we are chilled and stress free, we are in balance and can focus on finding food, relaxing with friends or family, engaging in romantic pursuits, and teaching or learning with a clear head. If the risk of a threat appears, is felt but not detectable and there is no obvious danger yet, we may be wary but are still good. In the presence of a detectable threat or predator, all systems are “go” and either we freeze, run away, or fight. As presumed prey, our singular goal is to escape and fight only if we have to; the predator's goal is to capture and consume.
When there is a smell, sound, glance, taste, or perception of danger, our brain adapts to multi-sensory mode. Fear is not produced from only one brain region but is a network of brain structures that coordinate responses (see Appendix A). The amygdala, an almond shaped structure located in the temporal lobe is one of those. The amygdala is a part of the brain's ancient neural circuits and part of the limbic system and receives inputs from our senses. The limbic system supports emotion, behavior, long-term memory, and input from our senses. It influences how we respond to stress and the stress response by its interaction with other brain systems like the endocrine system and autonomic nervous system. The amygdala plays a role in fear expression, fear learning, and fear extinction. Emotional, behavioral, and physiological responses to fear are all mediated by the amygdala (Gozzi et al. 2010). The amygdala has multiple nuclei that function to enhance fear and messaging to engage the stress response in the brainstem or to engage the prefrontal cortex for behavioral control and resilience coping (Sinha et al. 2016). Sitting next to the amygdala lies one of the oldest brain structures; the hypothalamus. It relays fear-related information to the amygdala and prefrontal cortex and is a critical structure for learning, memory, and fear behavior (Hasan et al. 2019). Oxytocin, a neuropeptide produced by the hypothalamus and released by the pituitary gland, plays a role in the behavioral response to fear, specifically freezing as an expression of fear (see Appendix B). It's commonly known as a bonding hormone after childbirth and may explain why women when stressed will “tend and befriend” bringing others close by in response to threat.
The hippocampus is a brain structure that arches over the amygdala and hypothalamus. It is a part of the limbic system and regulates motivation, emotion, learning, and memory. Fear is associated memories and the hippocampus stores long-term memories, making them harder to forget. People who have PTSD, OCD, or depression may have dysregulated limbic systems that make fear extinction or lessening the trauma of memories much harder.
Fear, whether learned or acquired, triggers a fear response. The fear response triggers adaptive behaviors including activating the amygdala and the autonomic nervous system through the vagal nerve and the Hypothalamic-Pituitary-Adrenal (HPA) axis that controls the stress reaction or stress response. The stress response is generated by any potential or real threat or stress and triggers the HPA to release cortisol throughout the body. As a result, the brain and body focus resources on survival: release fats and glucose into the bloodstream for energy; increase the heart rate; inhibit digestion; suppress the immune system; and slow down reproductive hormones. Acute stressors, if resolved, allow the body to recover but chronic stress contributes to cardiovascular disease, anxiety, depression, diabetes, and impairments in learning and memory. When stressors are removed, both brain, body and psychological impairments can be reversed.
The prefrontal cortex, a part of the cerebral cortex covering the frontal lobe allows us to understand, process, and behave in a way that integrates our fear and stress into thinking and behaviors to regulate our stress and fear response. Our prefrontal cortex has two lobes: the dorsolateral prefrontal cortex and the medial prefrontal cortex that play a big role in coping, resilience, memory, and how we think about our circumstances that can help overcome, learn from, and extinguish fear. Using our cognitive thoughts to reframe and reappraise, listening and watching how others process fear and tapping into our courage to persevere through fear begins and ends in our brain.
Our brain wants us to be safe but not afraid. We have the cognitive tools to switch from fear to courage and adapt to fearful circumstances.
In a classroom setting with high levels of anxiety or stress, you can see how learning may be impacted based on the outside environment and internal perception. Our ancestors were masters at changing environments and solving problems under unique and new circumstances to allow us to survive and thrive. Students and educators can utilize the same advantage with awareness and training, if we use our head and heart.
Another evolutionary asset that is on our side is our tendency to form close bonds. As we said above, our fear-learning unfolds over the course of our life in relation to our caregivers. After a baby is born, its brain is dependent on sensory stimuli to grow, adapt, and change structure and functioning. The length of time for this development is longer in humans and necessary for social bonding. The human brain takes the longest for maturation and is impacted by structural factors like environment, stressors, economic resources, genetics, and social stability. Humans' extended infancy and childhood mean we have a multitude of influences on brain and body development. At birth, our brains are 30% of the size they will grow to as we mature into adults. By the age of three, the brain is 80% of adult size, and 90% by the age of five. That means childhood influences, exposures, and resources from birth to five can have a long-lasting impact on brain functioning.