Let's set the scene, you've just got home after a long, gruelling day at work or maybe you've been travelling. You put your key in the front door, turn and you're in.
Finally, home. You breathe a sigh of relief but before you're know it, you're up the stairs and unleashing hell on your porcelain throne.
"This is indeed a very familiar story," says Nick Haslam, a professor of psychology at the University of Melbourne.
Speaking to The Atlantic, professor Haslam said it was all to do with 'unburdening' and is the opposite of traveller's constipation.
He said: "Most people feel more comfortable going to the bathroom in familiar-and private-surroundings.
"In my view the experience of 'unburdening' upon returning from a trip is largely a Pavlovian response: The home is a safety signal, signifying that this is the right place to go.
"If there has been any inhibition or retention at all during the trip the relaxation response is likely to kick in when you come home."
But is there something more, something deeper to our tummy troubles? Well, according to Jack Gilbert, a professor of surgery at the University of Chicago, where we choose to do our business could offer a window into our very soul.
"What is 'more comfortable?'" Professor Gilbert asks. "Why do you feel more comfortable at home?"
The easy answer is familiarity, you're used to your own house, there are no strangers beating down the door asking you to hurry up.
Professor Gilbert explained to The Atlantic: "Right, but that's not you thinking that, remember that.
"Unless you're highly spiritual, then the soul doesn't really exist. There's no ghost in the machine. You're just a sensory programming device."
He goes on: "All you're doing, when you try to recall something, is triggering sensory simulacra of that experience. 'More comfortable' is an emotional state, but emotions are physiological responses. So 'more comfortable' is a physiological state. It's a way in which your body responds to its environment.
"When you get back into your home, your glucose tolerance will change. Your adrenaline pumping will change, and the energy sensors of your muscles will change, altering your actual respiration, how much energy your burn, and how much fat you deposit.
"All of these factors influence how quickly food moves through your gut."
I.e. dropping a log.
Professor Gilbert says this means just the mere sight of your toilet, therefore, is enough to set you off.
He explains: "You have a lot of experience defecating and urinating in your preferred toilet which becomes strongly associated with those acts, so just being in its presence triggers the relaxation response that allows you to release the inhibitions that led you to 'hold it in' while in unfamiliar surroundings.
"We are essentially automata responding to environmental cues. I'm pretty sure I can train you as a human being to pee when you smell peppermint. That's an example of how much of an automaton you are. It would be technically possible to do that."
And though the idea of asking why we poo where and when we do may sound fairly frivolous, Professor Gilbert says it's anything but.
He says it is 'paramount to the fact that we are not in control of our environment. There is no free will'.
Something to think about next time nature calls.
Featured Image Credit: Universal Pictures
- Pelvic floor expert explains why you should never wipe more than three times after going for a poo
- Why I do what I do: Autopsy technician found a live snake inside dead person's body
- Pelvic floor expert explains why you should stop going to the toilet 'just in case'
- Doctor Explains How Often You Should Poo