A recent article in New Scientist credited evolution for our sense of fear:
“Evolution has given us an inbuilt fear factory. But by engaging a different way of thinking we can stop panicking and weigh up the real risks.”
The magazine makes a distinction between two kinds of approaches to fear that are known as system 1 and system 2 thinking:
“System 1 is the product of evolved biases shaped over thousands of years.”
It quotes author Dan Gardner, who brings up the standard Darwinian explanation:
“If you saw a shadow in the grass and it was a lion and you lived to tell the tale, you’d make sure to run the next time you saw a shadow in the grass.”