Stepping in poop, eating rotten food, standing downwind from a garbage truck: we’ve all been there, and it seems the disgusting memories stay with us with good reason. Research has shown how disgusting experiences are remembered with more details about smells, tastes, and touches compared to scary or morally questionable ones. 

While unpleasant on the mind, it could be an adaptation that helps us survive.

Why do we find things disgusting?

Human beings try to avoid disgusting situations, and with good reason. If we were totally chill sitting in piles of other people’s filth, there’s a good chance we’d eventually meet with the consequences of our actions in getting sick.

Disgust could be a benefit in helping us to avoid threats we detect with our "close up" (aka, proximal) senses, like touch, taste, and smell, while things we detect with our "further away" (aka distal) senses might be better remembered through sight and sound.

What they did

To test the theory, scientists asked participants in a study to recount disgusting stories, from the most ever to the most recent. They also asked them about experiences that were morally repulsive, and ones that were scary. They then asked the participants to rate how heavily the senses contributed to their memory of the event. 

What they found

The results showed that disgusting experiences are more closely tied to the proximal senses: smell, taste, and touch. By comparison, morally repulsive and scary experiences are more often remembered by the distal senses, which are sight and sound.

This supports the disease hypothesis as those proximal senses are crucial in avoiding things that could make us ill. For example, we look to the smell, taste, and texture of milk as an indicator of freshness over its sight and sound. However, if you were once hit by a car, you might more vividly remember the sound of its approach over whatever you could smell at the time.

What we learned about ourselves

When discussing the story, Managing Editor Katy Evans shared that she’d had a harrowing run-in with a surprise and overpowering dose of truffle while cooking. Not quite disease avoidance, but you can imagine how the conversation went after that. So, here’s some IFLS flavor in the form of disgusting taste, smell, and touch stories. Enjoy!

Content Creator, Eleanor Higgs: Third-year zoology students like to believe that we're made of strong stuff when it comes to dissections, but put 50 students in a room on a hot summer's day with 25 rotting mackerel and you'll find even the strongest of stomachs turning at the smell coming off those. 

Senior Journalist, Tom Hale: When my sister was around 12, she made coconut ice and made a pretty little box to present it in. The box ended up sitting on the window sill for weeks or months, and my dumb six-year-old ass decided to eat it. I was sick for like three days and now hate desiccated coconut.

Science Writer, Dr Russell Moul: I remember when I was doing my A Levels in psychology, I had to visit a primary school to observe some reception children playing and taking part in an experiment. Despite my best efforts, the kids wouldn't leave me alone and kept jumping on me as I tried to conduct the experiment. At the time, I had long-ish hair. I still remember leaving the place and later running my hand through my hair only to find a large patch that was stuck together with something that was "tacky". As I removed it from my hair, it turned out to be a massive clod of partially dried snot from one of the little gits. It has been 19 years, and I still vividly remember how it felt, both in my hair and then in my hand.

Sci-comm Legend, Rachael Funnell: The year is 2023 and I am clearing the mess of communal bins outside of my poorly managed shared housing property. Dog walkers have taken the disarray as a sign that it’s a free-for-all for dumping poo bags, and oh boy, have their numbers grown. I eventually caved and decided to clean the mess myself, and I’ll never forget the smell. One of the bins had filled with rainwater and turned a poo bag into a sort of cursed tea bag, swollen with water that had somehow got in and wouldn’t come out. 

Senior Staff Writer, James Felton: Don't get how you all can remember the taste of stuff, I'd just sit there remembering eating sausages.

Good to have you on the team, James.

The study is published in Royal Society Open Science.