NEW YORK (CBS Local) – Even though Halloween 2017 has already come and gone, the human race’s revulsion for creepy crawlers is apparently here to stay.

A new report said that a study of babies has found that humans don’t just learn to be scared of spiders and snakes, they are actually born with the fear of those creatures already in their brains. The report, published in Frontiers in Psychology, tracked the responses of a group of 6-month-olds when they were shown images of the frightening animals compared to images of fish and flowers.

Scientists from Germany and Sweden said that the babies’ eyes opened much wider when presented with spiders or snakes, signaling the human “fear-threat reaction” at work.

“Change in size of the pupils is an important signal for the activation of the noradrenergic system in the brain, which is responsible for stress reactions,” neuroscientist Stefanie Hoehl said in a press release. “Accordingly, even the youngest babies seem to be stressed by these groups of animals.”

The researchers theorized that the results seen in the 32 infants show that humans have grown to view these scary-looking creatures as a danger, and have passed that fright down to their ancestors. “This particular reaction upon seeing spiders and snakes is due to the coexistence of these potentially dangerous animals with humans and their ancestors for more than 40 to 60 million years,” Hoehl added.

The study also said that combining this inherited fear of scary critters with other factors, like your parents’ reactions or if your brain has an overactive “fight-or-flight” response, can lead to a person suffering from a severe phobia of spiders and snakes.