Have you ever wondered why some people love things like apple and mayo sandwiches or chicken feet, while the mere thought of those dishes might make another person want to throw up?
Rachel Herz is studies this kind of stuff. She's a neuroscientist who specializes in taste and smell. She's also the author of Why You Eat What You Eat, and The Scent of Desire. According to Herz, whether or not you think something is unpleasant has to do with the meaning of whatever it is to you.
"The emotion of disgust is highly learned," she says. "You need an intact, healthy brain in order to turn the mechanism on. But after that, it’s really a function of our experience, culture, and learning."
Herz adds that what we deem as disgusting is malleable and can change based on the situation we're in and the meaning we ascribe to whatever it is we think we’re perceiving.
"If you were sitting in a fancy French restaurant and started smelling something and noticed a waiter with a tray, you’d go, 'Oh, it must be the cheese course; I’m excited, I’d like to have some taleggio.’ But if you encountered that exact same smell while walking down an alley behind a dive bar, your thoughts would construe the aroma as something totally different," she explains. "And you’d probably feel totally disgusted."
We don't only experience a gag reflex when we find something disgusting, says the expert. There's a lot more going on in our bodies than many of realize. For example, Herz reveals that disgust can trigger physiological responses like a drop in blood pressure and an increase in sweating.
"In extreme cases, you can faint or even vomit," she adds. "Serotonin gets suffused into the stomach, which is actually an adaptive measure to help initiate vomiting. From a primitive perspective, it’s about protecting us from being contaminated from something on the outside getting into our bodies."
Interestingly, there's also a reason why we make a certain face when we see, smell or taste something gross. From an evolutionary standpoint, it's to shield our body from the outside. So the eye squinting, for example, is a bid to take in less light so that we can't clearly see the disgusting object.
"In addition, the nose scrunches up and nestles around the cheeks, which closes air off to the nostrils so you can’t catch the smell as well," says Herz. "And our mouths purse as a means to keep things out, or if something got in, it’s a way to get it out. It’s all about protecting the holes on our face, as it were, from contamination."
