Are clowns really supposed to be funny? They terrify me. I was trying to think back and work out how it all started. Then I remembered there was that one time we went to the circus and a clown killed my dad.
The trouble with fear is we need it to keep ourselves safe, it’s the trigger that turns on our flight or fight response, and yet in an evolved world in which humans control so much of their environment, most of the time it is simply needlessly debilitating. We needlessly fear the things we cannot change, like death and taxes, and we fear the unknown despite all our opportunities in life appearing from there.
But spare a thought for sufferers of Urbach-Wiethe disease. Due to the destruction of their amygdala, a primal part of their brain, they feel no fear. Which in some ways must be liberating but must also make Thorpe Park, Jimmy Saville and 99% of the 10 O’clock News a bit of a let-down.
But new research at the California Institute of Technology in Pasadena has shown that fear is to be found in other parts of the brain too. Researcher Justin Feinstein managed to provoke fear in a Urbach-Wiethe sufferer known as “AM”.
Imagine if you had never experience fear, just how terrifying it must be to suddenly suffer it as an adult. But, by voluntarily putting a mask over her nose and mouth and breathing in carbon dioxide, “AM” suddenly thought she was dying and lifted her arms in panic.
Exposed to carbon dioxide levels of 35 per cent, Feinstein managed to scare “AM” and provoke intense fear in two other volunteers with the same condition (Nature Neuroscience, 001: 10.1038/nn.3323). Forget the therapy bills his volunteers may now incur, Feinstein’s results challenge the widely held belief that the amygdala is the centre of our fear response.
Pity the control group for this experiment. Before imbibing pure carbon dioxide volunteers with intact amygdala would, unsurprisingly, experience a rapid rise in heart rate beforehand. They were, after all, about to poison themselves. However, “AM” and the other volunteers had no anticipatory response. Though they experienced fear in the experiment they simply could not anticipate it.
‘This study hints that internal threats are processed differently by the brain than external ones,’ says Feinstein. There are chemical receptors in the brain which are activated by acid levels. Since carbon dioxide changes blood acidity it’s very possible that our emotional responses can bypass the amygdala and be triggered directly.
Now I know that nobody died in this experiment, and that it may help people who are in danger of harm through fearlessness or lead to even better anti-depressants or de-stress tablets. And yet I can’t help thinking Dr Mengele would be proud of this sort of experiment.
The future may be less fearful for some but it sheds a nasty light on the past. For all my aunts, uncles and cousins who were murdered in this way in the 1940s, now we know there was no simple falling asleep, terror of gas poisoning is hardwired in our brains.
Marius Brill is the author of How To Forget, available in all good bookshops now.
This article first appeared in