Much of what I write about concerns the human Fear System – our biological response to threat. Where it functions as it was designed to – switching on when danger threatens, and switching off when we are in a place of safety – then all is well with us. However, where it malfunctions, particularly where it fails to switch off when it is not needed, it has a huge impact on us, and is perhaps the key underlying cause of most physical and mental ill health.
In this post I want to look at three video examples which vividly demonstrate the Fear System in action.
I am using the overall description of “Fear System” to cover 3 responses to danger or threat. The first is the initial response of being alert to danger – going very still, holding the breath, trying to locate the source of danger. The second, once the danger is clearly perceived, is fight-flight, where the sympathetic nervous system triggers a powerful and sudden physical mobilisation to escape from the danger, and the third, when the danger is too close for escape, is tonic immobility, a bodily shutdown triggered by the parasympathetic nervous system, that can switch off a predator’s attack and open up the possibility of a last ditch escape, or render death less fearful and painful.
Our Fear System evolved over countless millenia in the crucible of one animal’s need to catch and eat another. I want to comment on three examples available on You Tube of prey and predator, which show various aspects of fight-flight and tonic immobility.
In the first example (click here) we see fight-flight in action as a springbok is chased by a cheetah. The springbok runs until it is caught, then puts up a fight until it is hopeless, then collapses. The collapse is tonic immobility in action – the heart rate and blood pressure have plummeted – the animal is effectively in a faint. The video then cuts to the aftermath of another chase where a cheetah has caught an impala. We see its limp body being dragged along by the cheetah, then lying on the ground as if lifeless, with its eyes still open – it is also in a state of tonic immobility. At this point the cheetah is chased off by baboons. Then the camera comes back to the impala – it still seems lifeless, but the camera focuses on a slight movement of the nostrils then a deeper breathing which moves the whole body. At this point the camera angle shifts and it’s hard to see what’s going on, but in fact the impala is shuddering. This is a release of the energy of fight-flight which was interrupted by the immobility collapse, and, along with the deep breathing is the natural way the body “resets” after major threat and is a key part of the mechanism by which the Fear System switches off. We then see the impala standing up – it does not need to run away as it is already in a safe place with the protection of the troupe of baboons.
In the second example (click here) a leopard has already caught an impala which is lying as if lifeless, eyes open, with its nose in the leopard’s jaws. A hyena is spotted and the leopard is distracted – notice how, when the cheetah releases its grip to look at the hyena, the impala’s head flops onto the ground. The “tonic” bit of tonic immobility refers to the fact that in this bodily shutdown, the muscles lose their “tone” or tension – hence the flop. (There is a huge amount of confusion in the literature over the use of the word “freeze” being applied to this state, and tonic immobility being muddled with “rigid immobility” – a totally different biological state. I will go into that when I write separately about Freeze)
The leopard is then further distracted by a couple of baboons which chase it off. The implala is lying completely still at first, then its abdomen moves as it starts breathing deeply, and you can see some movement of the eyelids. Then as it starts to right itself it shudders for almost a full minute, resolving into more gentle trembling – this is the “resetting” of the fear system referred to in the first example, but much more visible. Finally the impala is up and away.
In the third example (click here) we see another impala in fight-flight mode, and then collapsed, having been brought down by a cheetah. The cheetah, exhausted by the chase, is itself chased off by a hyena. However, as the cheetah and hyena face off against each other, the impala suddenly comes out of tonic immobility and makes off at high speed. (ignore the narrator’s uninformed “cunning dissimulation” comment). This is a good example of the “window of opportunity” that can open up after an immobility collapse, prompting a sudden switch out of immobility and back into fight-flight. With both cheetah and hyena still on hand, this is not a safe place, but the energetic escape will burn off the energy of the fight flight response, and the fear system will switch off once a safe place has been reached.
So the first two examples show a recovery from tonic immobility in what is now a safe place (protected by baboons), where there are a number of deep spontaneous breaths which expand the abdomen, followed by a period of shaking or trembling in which the tension and energy of the fight-flight impulse is dissipated (effectively “resetting” the fear system). The third example shows a window of opportunity for escape opening up in an unsafe setting, where there is a sudden switch out of immobility and back into fight-flight.
If you find this interesting, I would recommend reading Peter Levine’s book, In an Unspoken Voice. The first chapter gives an account of his experience of being hit by a car and shows how the same biological responses occurring in animals when a predator attacks its prey, operate in us as humans when we face major threat.