Though humans have some instinctual fears that drive avoidance behaviour, these are limited. The classic 1960 visual cliff experiments (Gibson and Walk), which monitored infants' behaviour beside a simulated drop -- they were protected in fact by a glass sheet -- were interpreted initially as evidence that all children share an innate sense that heights are dangerous.
However, repeated variations of these tests conducted since suggest that even this sense is acquired by babies learning to crawl, walk, fall over and get up again.
In 1920 another psychologist, JB Watson, rather unethically conditioned nine-month-old Albert to be terrified of a white rat by making a loud noise behind his head every time the rodent was produced.
We do share, it seems, a fear of sudden loud noises. However, this does not translate to it being common sense to avoid areas with ongoing loud noises, whether plant rooms or musical events, or to wear hearing protection when we can't avoid them.
It has also been suggested that, due to our evolutionary flaw of having poor night vision, we have an inherent fear of the dark. But that innate fear isn't enough to make regular checking of emergency lighting or fixed-wire tests common sense.
Aaron Butt, a safety and health specialist in industrial construction and maintenance in Canada, provides a colourful example of how all common sense has to be learned, either from experience or through training: "Common sense in northern Canada is not placing a wet tongue on a cold metal pole. In the southern US it's not lingering at the edge of a water body because of alligators."
Common sense is one of the most misused phrases in safety and health
Licking a metal pole would be an odd thing to do anywhere but it's easy to see how visitors from parts of the world where the most hazardous creature in the water is an angry swan might not have the "common sense" to stay back from the edge of water in Florida.
So, in the workplace it is frustrating to find "common sense" still prescribed as a control for a hazard with no explanation of what knowledge is needed or how it will be supplied and assessed.
What an experienced worker considers to be common sense could be a revelation for someone new to that working environment. You don't chock the wheels of your car when you leave it parked, even on a hill, so why would you assume that someone would know when to do this in a goods vehicle yard?
Try to think of one example of behaviour you consider to be common sense -- washing your hands, looking before you cross the road, taking your coat with you in case it rains. Probably everything you can think of you were taught by a parent or teacher so long ago you have forgotten who.
In Safety Myth 101 (2016), Carsten Busch writes that common sense is one of the most misused phrases in safety and health. As a non-native speaker of English, Busch points out how the meaning of "common sense" in English is not the same as its equivalents in other languages. In German, gesunder Menschenverstand is closer to "healthy sense", implying that something is the right thing to do in a given situation, not that it is a commonly held view or that everyone should instinctively know it.
In the first half of the 20th century it was a commonly held view that smoking was good for you. During the first world war, cigarettes were issued to soldiers in the trenches as part of their essential rations, and between the wars advertisers appealed to women by presenting smoking as an aid to weight loss. It was common sense to smoke, but not a healthy sense.
So search your organisation's risk assessments for common sense and replace the term with a definition of the competence or knowledge required, how you are going to achieve it, and what level of supervision is required until it is demonstrated.
Watch out too for implicit assumptions of a shared wisdom that all workers may not possess. And the next time a colleague remarks "it's just common sense" remind them of the words of another Canadian safety professional, Alan Quilley, who said: "Anyone who believes that they have common sense has simply forgotten who taught them what they know."
