Why spiders and snakes and things that crawl fill so many of us with dread.
The fear of snakes has plagued Sydney Masters as long as she can remember. Ms. Masters, a New York public relations executive, experiences an overwhelming panic-attack type of fear — shortness of breath, rapid heartbeat — whenever she’s near anything that slithers.
Several years ago, while she was walking in Washington Square Park, a man pulled out a gun, shooting in the air. At that same moment, she spotted another man carrying a boa constrictor wrapped around his body. “My big worry was not the gunman,” Ms. Masters said. “It was the boa.”
Priscilla Deniz, an immigration and trademarks lawyer based in Pembroke Pines, Fla., considers herself to be self-assured and confident, except when it comes to bugs, specifically cockroaches. “I can barely write the word without the hairs on the back of my neck standing up,” Ms. Deniz said. “My fear is so strong that I cry real tears when I see a cockroach.”
Ms. Masters and Ms. Deniz are far from alone. A 2018 Chapman University study found that 24 percent of Americans say they are afraid of snakes and lizards, and 22 percent say they are afraid of insects and spiders.
Why do so many of us respond so viscerally to snakes, spiders and things in the “creepy crawly” category?
It might be in our genes.
Peter Mezo, associate professor of psychology at the University of Toledo, said that “a potential explanation from an evolutionary perspective is that snakes, spiders and insects may have posed deadly risks to our predecessors, so those who learned of their danger and avoided them were more likely to survive. “In fact, we see similar biological preparedness among other primates, such as chimpanzees.”
One study by researchers at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany, and Uppsala University in Sweden found that these fears are innate. When babies as young as 6 months were shown pictures of snakes and spiders, the babies’ pupils dilated — a flight-or-fight response — when they saw photos of snakes and spiders, as compared to pictures of flowers or fish of the same size and color. The scientists suspect that this response may be “an evolved mechanism that prepares humans to acquire specific fears of ancestral threats.”
Just as fear may impart an evolutionary advantage by helping us to avoid potential predators, so may disgust, the aversion many of us feel to these crawling and slithering creatures.
A 2018 study from scientists at the Georgia Institute of Technology in partnership with the pest control company Orkin found that pests seen in a home elicit a neurological reaction of “strong disgust.”
“Insects in the home produced more disgust in the brain than insects in the wild, especially cockroaches,” said Dr. Eric Schumacher, director of Georgia Tech’s Center for Advanced Brain Imaging. “Our research suggests that we may be conditioned against pests in the home because they may be associated with contamination or illness. It’s not clear why cockroaches in particular elicit extreme disgust, although there can be many social and cultural factors that come into play that drive these emotions — familiarity, cultural norms, and so on.”
“Disgust likely evolved to keep us away from sources of pathogens,” said Tom Armstrong, assistant professor of psychology at Whitman College in Washington State. “Creepy crawly insects could be repellent because they tend to live in dark, damp places where bacteria thrive. Some may be human parasites, whereas others could transmit disease. While worms or maggots in food may not be harmful in themselves, they could indicate that food has been compromised by pathogens.”
John Mayer, a clinical psychologist and horror film screenwriter, suggests another reason so many of us feel disgust toward these creatures is that they seem to defy the natural order. “They seem to live forever,” said Mr. Mayer. “They are hard to destroy. Lightly flush a spider down a drain, and in minutes it is crawling back out of the drain. Squash some bugs, and they keep wiggling. Add on that they seem to multiply by the millions. Then, to all this, they look abnormal — weird heads, spindly legs, wings, strange color combinations. These are not living creatures that convey cuddly, cute affection — rather, danger. And, hell, some bite.”
Yoshinori Tomoyasu, who grew up in Japan and moved to the United States as a researcher studying insect evolution and development, said “many things are surprisingly similar between the U.S. and Japan, but with one exception — insects are not so ‘popular’ in the U.S. This was a big surprise for me, especially as an insect scientist. In Japan, insects are very close to us, both physically and mentally.”
Dr. Tomoyasu said that keeping insects as pets, especially rhinoceros and stag beetles, is very popular for kids in Japan. Rhino beetles, for example, are a symbol of strength, and kids who can catch big beetles are the “cool” kids there, he said.
“Insects are embedded into Japanese culture, which is evident from many insect-related phrases and proverbs we have in Japan. For example, when you have a hunch, you can say, ‘I had news delivered by a bug,’” Dr. Tomoyasu said. “When you are in a bad mood, you can say, ‘My bug is in a wrong place in my body.’”
In the past 10 years, he has observed more insect-related products being marketed to American children, such as bug nets and cages, as well as books and TV shows about bugs, which may help a new generation to face them with less fear and disgust.
“Insects are truly amazing,” said Dr. Tomoyasu, a biology professor at Miami University, in Oxford, Ohio. “They are the dominant group of organisms on this planet — except for microscopic creatures such as viruses, bacteria and fungi — accounting for nearly three-quarters of described animal species, while we mammals are minorities.”
“Considering the drastic climate change and the significant human population growth that we are facing, we will soon encounter the serious problem of securing our food,” Dr. Tomoyasu said. “Some insect species are edible, nutritious and easy to culture within a small space. Insects have already been used as food in various regions around the world.”
He noted, for example, that wasp larvae have been an important food source in some regions of Japan and are now considered a regional delicacy.
“Some researchers are working on enhancing their nutrition and edibility through genetic modification,” he said. “Those insects could be the future of our food.”