It’s possible some people find mayonnaise off-putting because it’s just a bit too... excitable.
“Its texture is what makes it most repulsive,” Herz told HuffPost. “It has the ability to wobble and does not sit inert, even though it is not animate. The inert taking on qualities of an animate object can create feelings of disgust. Its moving implies a living thing, and living things can contaminate you.”
One of the main functions that disgust serves for us is to help us avoid contamination. If something moves when you don’t expect it to, or in a way you don’t expect it to, your mind can generate a feeling of aversion as a way to protect you from whatever this weird thing is.
Even if you’re eating mayonnaise in a sandwich, where you won’t see it move, your mind might still associate mayo with unnatural behavior, which can render it inedible to you.
Mayonnaise reminds people of bodily fluids.
“I suppose people are disgusted with mayo because it has the consistency of pus,” Miller told HuffPost. “Some things are more likely to generate disgust than others, and bodily fluids and rot are two of those things.”
Semen, pus, fat: Mayonnaise doesn’t not resemble these substances, and that might not be what you want to be thinking of at mealtime. Some people are disgusted by bodily fluids subconsciously as a result of the fear of contamination. hacks and juicy stories to get you through the week.
Mayonnaise is the wrong temperature.
As a general rule of thumb, Miller said, “unless [a substance is] ice cold or in flames... the potential for disgust is greater.”
Vanilla ice cream, for example, is white and viscous, like mayonnaise. But it doesn’t provoke the same reaction, because it’s frozen. Anything that’s close to room temperature is also close to the temperature of the human body, Miller explained. Sure, mayonnaise isn’t served at 98.6 degrees Fahrenheit, but it isn’t served frozen or fried, either.
Anything non-human that reminds people of human life has the potential to induce disgust ― that’s why the uncanny valley is a thing. “Is there anything more revolting than the science of human life?” Miller said.
A hate for mayonnaise is learned.
There’s often a cultural component to disgust, which can help explain why mayo is regarded dubiously in some countries (like the U.S.) and beloved in others (like Belgium).
“Our response to disgust is actually learned,” Herz said. “There’s no innate understanding that mayo is like a bodily fluid or that we should have an aversion to bodily fluids, but once we do have that association, it does really elicit a real emotion of disgust.”