As part of game night at a party, you are given a box with an object that you have to identify solely using touch and smell. You are blindfolded and are asked to put your hand in the box. It feels squishy, soft yet crumbly, sticky, smelly, and although it is only a mixture of sour cream and breadcrumbs, you jump out of your chair because it feels so much like poop!
Not to say that we should touch poop every now and then to understand its texture, but our brain has an image of what it might feel like to touch poop, and we all keep away from anything that smells even remotely of poop! Animal poop, our poop, squishy poop, solid poop, yellow poop, being disgusted by poop is almost universal, and there is a solid reason for us to feel this disgust.
How do we produce stools and what is its composition?
The food we eat to survive passes through our digestive system. As food passes through the digestive system, the small intestine absorbs about 90 percent of the water content and sucks in the nutrients our body needs from the food we just consumed. What is left now is the indigestible content of food which makes its way through the large intestine which is where the undigested food truly turns into poop.
The large intestine mainly absorbs the remaining water from the undigested food, but bacteria within the large intestine perform a little more digestion. At the end, we have a solidified mass of stool.
This stool generally has three components in varying percentages – water, bacteria, and undigested dietary fiber. Stool is approximately 75% water, and the solid matter is made up of 25-54% of dead and live, harmless and pathogenic bacteria while the rest is undigested fiber.
Why does poop smell?
The most disgusting aspect of poop is its smell. Poop releases a host of volatile gases as a result of the microbial activity in our gut. The common gases are carbon dioxide, oxygen, hydrogen, and methane, but the main culprits for the infamous stink are indole and skatole. They are formed due to intestinal bacteria acting on the amino acid tryptophan which is present in our diet.
Among the compounds, skatole has a stronger odor and makes us cringe more on inhaling it.
Why do we feel disgust?
The bacteria in our poop can cause some crappy diseases such as cholera, food poisoning, and diarrhea. Apart from the natural defense barriers of our body like our skin and our sophisticated immune system, we also have a behavioral immune system that prevents us from getting too close to things that could be infectious, such as poop.
“Disgust” is a part of this system and is a rather basic emotion observed in many species. Most bodily secretions pose the risk of infecting us with disease and disgust is considered to be a disease-avoidance mechanism or hygiene provoking emotion.
As evolution and natural selection would have it, those animals and species which managed to stay away from pathogens survived and evolved. In humans, disgust happened involuntarily without any conscious decision to “feel disgusted” and thus, when encountered by disgust elicitors like poop – it led to more hygienic practices and thus avoiding disease.
Disease avoidance behavior is not unique to humans, even lobsters stay away from other sick lobsters!
Did we learn to feel disgusted?
Disgust as an emotion has intrigued many scientists and various brain studies and investigations have revealed that when faced with a disgust generating stimulus, significant brain activity is noted in the anterior insula and amygdala regions of our brain.
It’s almost like we are hardwired to feel disgusted at our feces because of the risk it poses to our well-being owing to its composition. See the full picture now?
Poop – composition (disease-causing bacteria amongst other things) – stench – our own universal “yuck” response is all a part of a disease avoidance tactic.
A final word
Disgust is a strong universal emotion but occurring in varying intensities. We all feel disgusted, but some things may gross you out more than others. And in cases you may be able to tolerate something another finds disgusting. The mother of an infant isn’t as disgusted by her child’s poop. Here the mother’s feeling of disgust of her child’s poop is actually down-regulated.
Similarly, the fact that we are more disgusted at the sight of someone else’s poop than our own is because of the awareness that someone else’s poop brings with it novel pathogens, and that subconscious awareness makes us shudder more than witnessing our creation in the washroom!
We eat, we poop, we repeat and thankfully poop is a disgust elicitor and so we stay away from it and all the disease-causing organisms it harbors. Poop disgust in short is a blessing in disguise and thank God for our wonderful digestive system and behavioral immune system which work to keep us alive and safe.
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