Fear keeps us alive; it primes our bodies to help us avoid or confront danger, and has been described as one of our ‘basic emotions’. But where does fear come from, and what would life be like if one were completely fearless?
Scared of snakes such as this Spotted Python? Image: Wikimedia/Vicki Nunn
American researchers have recently had the chance to find out. They have been studying a woman, known as ‘SM’, with a rare condition which means part of her brain called the amygdala doesn’t work. She is also incapable of experiencing fear, although she can feel the full range of other emotions. The finding supports the idea that the amygdala is responsible for our fear response.
According to the lead author of the study, “Because SM is missing her amygdala, she is also missing the ability to detect and avoid danger in the world. It is quite remarkable that she is still alive.”
To test her fear response, SM was exposed to fearful stimuli such as snakes and spiders, a haunted house and horror films and her response monitored. SM never showed a fear response, and never reported feeling afraid.
Most surprisingly, this even applied when she was holding animals that she claimed to be afraid of. According to the researchers, SM was happy to handle the animals, and was confused by her own behaviour when the researchers pointed out that she had said she was afraid of such creatures.
What about this kimura spider? Image: Aiko Tanikawa/Wikimedia
But what can come from the study of someone such as SM? Potentially, the findings could help doctors treat anxiety disorders. The researchers are also involved with helping soldiers suffering from post traumatic stress disorder – an anxiety disorder caused by experience of a traumatic event. Understanding where fear comes from could one day help doctors treat PTSD by switching off or reducing the fear response that causes the disorder.
The study also demonstrates the importance of small-scale case studies in science. Whereas experiments including large numbers of people and statistically significant results rightly play a major role in much scientific research, there is still a role for smaller studies.
This is particularly true in psychology and other social sciences, where it is impossible or unethical to experimentally modify the participants – no researcher would ever consider deliberately creating brain lesions in people to learn about their brain structure! In these cases, study of rare cases such as SM can allow researchers to access information they cannot learn through other methods.
Feinstein, J.S., Adolphs,R., Damasio, A., & Tranel, D., The Human Amygdala and the Induction and Experience of Fear, Current Biology, In Press. Available online 16 December 2010. DOI: 10.1016/j.cub.2010.11.042.
Hypothesis Now 