December 6, 2021

I, Science

The science magazine of Imperial College

What would it be like to live your entire life without feeling fear? It’s not all plain sailing ...


“You asked me once, what was in Room 101. I told you that you knew the answer already. Everyone knows it. The thing that is in Room 101 is the worst thing in the world.”

Room 101, from Orwell’s Nineteen Eighty-Four, contained everyone’s worst fear. For the protagonist Winston Smith it was rats. For others it might be as sensible as snakes, or as bizarre as flowers. Say what you will, but everyone has some sort of fear.

Or do they? In the United States a woman, known only as S.M., has Urbach-Wiethe (UW) disease, an incredibly rare genetic disorder with only 300 or so cases recorded in medical literature. One of the symptoms in UW disease is the destruction of the amygdalae, almond-shaped groups of nuclei embedded within the brain.

The main impact of this destruction is the complete absence of fear within patient S.M. A group of scientists attempted to scare her with, amongst other things, poisonous snakes and arachnids, horror films and haunted houses. But they couldn’t perturb S.M. Only recently have researches found something that does trigger a fear response in UW sufferers: high concentrations of carbon dioxide in the blood. The fear of suffocation, simulated by breathing in high quantities of carbon dioxide, prompted the patients to feel fear for the first time in their lives. This suggests that the amygdalae, whilst important, are not exclusively the domain of the fear response.

However unpleasant fear may be, S.M.’s case highlights the role it has to play in human evolution: S.M.’s lack of fear has led her to handle dangerous animals that most sane people would seek to avoid. Just as pain is a protective mechanism to stop us from inflicting further damage upon ourselves, fear probably prevented early humans from running headlong into danger. Fears of snakes, spiders and other such creatures is likely a throwback from those times, and partly explains why people still display seemingly irrational fear responses towards harmless European animals.

But what if, using knowledge from S.M. and other UW sufferers, we could ‘shut off’ fear? Could we create super soldiers capable of fearlessly charging into battle? Or fire fighters who run headlong into burning buildings? Despite the damage to her amygdala S.M., is otherwise normal, so selectively dampening or even eliminating fear in this manner could prove extraordinarily useful.

Such an on/off switch would have to be carefully controlled. As handy it might be, a complete lack of fear also means no longer fearing death. Already servicemen, fire fighters, and those in other high-risk occupations put their lives on the line. Hypothetical users of a fear switch would have to accept that their lives would be placed at even higher risk.

But controlling fear is still some way off. As the case of S.M. shows the amygdala plays a large role in controlling fear, but its function would need to be clearly understood before it could be efficiently turned on and off ‘as needed’. In the meantime you’ll just have to man up and ignore that innocent garden spider in the corner of your room. The little guy isn’t going to hurt you.


IMAGE: Tomasz Krawczak