For instance, humans have an evolved fear-of-snakes mechanism that is activated by stimuli that have the features of a snake, which then produces a quick, automated response to cope with this threat.
Israel ultimately came to believe that a threat was evolving, fearing that ships coming into port could transport weapons.
That's why we evolved to fear for our privacy.
Her research has shown that humans aren't always faster at detecting snakes than other threats, including guns and cars, which we haven't evolved to fear innately.
"We've evolved with fear as an adaptive mechanism," she says.
People will say it's because these critters carry diseases and we've evolved to fear them, but I don't think it's that.
The debate on nuclear power has evolved, with fears of global warming prompting some officials, including House Speaker Nancy Pelosi, Democrat of California, to say expanding nuclear plants has to be considered.
As a global community, we are being called to exercise different muscles -- to evolve beyond fear, bullying and intimidation.
"Fear evolved to keep you away from large animals that want to eat you from the outside," says Valerie Curtis, a behavioral scientist at the London School of Hygiene and Tropical Medicine, who wasn't involved in the study.
Fear evolved in order to protect us from man-eating tigers and poisonous snakes, giving us a much-needed burst of adrenaline to save our lives when sprinting from a predator or natural disaster.
While the brain definitely evolved to care about "us," it also evolved to separate from, fear, exploit, and attack "them" - and those ancient, neural mechanisms can quickly grab hold of you.
