Big Kahuna - the Smart Sphincter

The eye is a wonderfully complicated mechanism and the ocular spinter is one of the more remarkable components of that machine; its autonomic control of the pupil in response to light helps us survive by giving us an optimal viewing lens under all conditions.

Its more subtle response to emotions interactions with others shapes – at what is usually at the subconscious level – our relationships, subliminally affecting our social successes and failures.

But I’ll suggest that there is another sphincter that performs equally important and sophisticated functions that also shape our culture and effect our relationships – the Big Kahuna of sphincters. The anal sphincter. While it is more well known than the ocular sphincter or the sphincter of Otti, most of us never give a thought to its importance and, yes, its innate intelligence.

All creatures that take sustenance from the environment process that input and, after extracting what they need from it, poop. Whether you are bacteria, a polar bear, or Queen Elizabeth the same rule holds; input, process, discard the residue as excrement. However, most life forms do the excretion part without giving it much thought. Some domesticated animals appear to have some awareness of the social implications of this process – your dog or cat usually knows when and where it should discharge its excrement and therefore has conscious control over its anal sphincter.

But somewhere in the distant past, humans elevated the intelligence of the anal sphincter to a level of sophistication unprecedented in the rest of the animal world. Once humans have reached the age of two or three years old, they know when and where it is appropriate to defecate. And that is the most minimal level of social sophistication – as we grow beyond infancy, the anal sphincter acquires the ability to distinguish between gaseous, liquid and solid discharges. And even to control gaseous discharges depending on social settings: it’s ok to fart in the locker room with the guys, but not ok to pass gas noisily in a formal setting with mixed company.

We’ll learn more about this major ring muscle later, including discovering the origin or ‘he’s just blowing smoke up your ass’.