Fear is a chain reaction in the brain that starts with a stressful stimulus and ends with the release of chemicals that cause a number of physiological changes in the body. Fear elicits what is generally known as the ‘Flight or Fight’ response – although there are 3 additional response/reactions that may be aroused according to the context of the stimulus. The fear response is a survival mechanism and has evolved over time. Fear is a normal human reaction- a built in survival mechanism that involves our mind and body. Fear serves a protective purpose of signaling our body to danger and preparing us to deal with it.
Some of the sensory data that we take in leads to conscious thought and action, while other stimulus produces an autonomic response. 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. However research has discovered that certain parts of the brain play central roles in the process.
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 doorframe 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 works 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.
For employees, knowing that the “butterflies” in their stomach or the muscle tension in their neck is part of the body’s normal response to stress can help them feel empowered to make changes. Understanding the physiological mechanism of the fight or flight response can provide people a sense that the “machinery” of the body can be manipulated in a healthy, adaptive way to respond to stress. Teaching employees about the physiological effects of the ‘flight or fight’ response will provide them with an understanding and awareness with regard to the physical experience their bodies will undergo during times of fear or stress. This knowledge, along with strategies to control these responses (such as strategic controlled breathing) will ensure the individual is better equipped to respond appropriately in times of danger.
The physiological changes that occur during the flight or fight response include the following:
- A surge of adrenaline leading to an elevation of blood pressure and heart rate aimed at increasing cardiac output to meet the challenge; and also in case of blood loss, to maintain circulation;
- An increase in respiration – the intake of oxygen and removal of carbon dioxide – because of an anticipated increase in energy expenditure;
- Mobilises blood glucose and fats as fuel for this sustained energy expenditure;
- Endorphins are released into the body;
- Diversion of blood-flow to muscles and away from the gut with the gut’s motility almost ceasing;
- An increase in platelet adhesiveness resulting in the blood becoming ‘stickier’ to assist with clotting;
- Activation of inflammatory hormones (e.g. cortisol, cytokines, interleukins etc.) which play a role in healing damaged tissues including accelerating cell replication and laying down new blood vessels; and
- A short-term mobilisation of white blood cells to protect the body if its defences are breached.
At the end of this session the learner will be able to:
- Explain the flight or fight response.
- Detail the physiological changes that occur during the flight or fight response.
- Identify methods of controlling the physiological responses during the flight or fight reaction.
- Explain the fear reaction and its relationship to the flight or fight response.