I'm at the age where half of the adult conversations in my life are about one teenager or another in my extended social circle doing something that lacks "common sense." This seems to frustrate and anger adults.

But it doesn't frustrate me, for the same reason I don't expect my toaster to mow my lawn. A young person's brain doesn't have a fully developed prefrontal cortex, and that's the part of the brain that imagines future consequences of current actions. (Please correct me if I got the brain region wrong.)

I've also noticed - and this is purely anecdotal - that some people seem to be born with full prefrontal cortex function, in terms of imagining the future, and others don't develop that ability until adulthood. In my case, by the age of six I was planning my entire life through retirement. (That's literally true.) Obviously I've had to revise the plan often, but I've never had less than a fully-practical lifelong plan.

That's why I worked hard in school to get good grades. It's why as a kid I managed to stay out of any kind of trouble that would follow me. It's why I've never had a serious injury doing dumbass things. The downside was that I worried about the future more than a kid should. It wasn't a healthy situation.

Despite my nerdish impulse for long-range planning, I had no "common sense" as a kid. And that's probably because what passes as common sense is nothing but pattern recognition - or "experience" as we like to say - and kids haven't seen enough of life to recognize many patterns.

I tell a story in my new book about going to my first real-world job interview at the age of 20. I had no mentors in my life to advise me in the ways of the business world. I grew up in a town with 2,000 residents and I had never even met a "business person" per se. My job interview was with a major international accounting firm.

My common sense told me that the last thing I wanted to do in a job interview was lie, especially if the lie would be easily detected. So instead of wearing a suit to the interview, which would have required acting like a huge phony, I wore my casual student clothes. The interviewer already knew I was a senior in college, so why would I present myself in some false way to a person I wished to impress? My "common sense" said I should be honest in my appearance, to get off on the right foot.

The interviewer took one look at me and showed me the door. He said, "I don't think you know why you're here." Ouch.

As the years passed, I saw enough patterns to realize that looks can often be more important than substance. But nothing about it is "common sense."

My point is that a normal, healthy brain doesn't have some magical ability called common sense. The pre-frontal cortex is either fully-formed or it isn't. And you have either seen a lot of patterns in life or you haven't. Sometimes logic matters in our decision-making, but not often.

The idea of "common sense" feels like magical thinking to me, similar to the notion that we have a "mind" that is more than the sum of our brain's chemistry and architecture.

As a descriptor, "common sense" feels dated.

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Feb 3, 2014
A long time ago, it was widely known that children needed to know the basics of avoiding dangerous situations as early as possible. A set of very short interesting and scary stories were created to give children the basics through rote repetition so they could learn from them as soon as their brains were developmentally ready. We now call those stories "nursery rhymes" and "fairy tales". I think this base set of "experience" was designed to literally teach children common sense. There were also adult stories for teaching more subtle concepts and tricks that every adult needed to know about. Those stories were called "morality plays". Star Trek the Original Series is a fine example of modern day morality plays.
Feb 3, 2014
I don't have the issue you do with the notion of "common sense," but I do have a similar objection to the notion of "intuition."

Posts like this one and the last few are the reason I originally became a fan of this blog. Happy to see a reprieve from book promotions for a little while.
Feb 3, 2014
maybe "contextual awareness" would be a better term.
Feb 3, 2014
I think Scott is right that 'common sense' is not a real thing, but only in terms of it being a misnomer. What we regard as common sense is really an expectation of rational behavior based on knowledge thought to be common, as in 'everybody knows...'

Where this expectation is frustrated is when we encounter individuals who are surprisingly ignorant of knowledge that we expect another person to have, or when the behavior displayed is confusing to an observer who thinks himself rational. Scott's story about the interview is really about ignorance of certain social protocols, which he has since become educated in.

People tend to believe that the knowledge and values common to their immediate group are also common to their society at large. When the actions of an individual or group show this to be false, it is easier to ascribe some flaw in the people doing those actions (that they lack common sense), than it is to concede that our immediate group is not, in fact, representative of the society at large.
+3 Rank Up Rank Down
Feb 3, 2014
I'd define common sense as the application of a few basic principles in the most rudimentary of fashions.

For example, I'd say it's "common sense" not to wear shorts and a T-shirt when it's 10° F outside and you're going to be waiting around for a bus at an unsheltered stop for 20 minutes.

Another example would be that it's "common sense" not to try to grab things out of a hot oven with your bare hands.

Yes, you have to learn these behaviors, but once you know how heat/cold work, you can extend them to multiple things. It's "common sense" that just about ANY hot thing can burn you, once you know that ONE hot thing can burn you. Especially if you've burned yourself before. :)

+6 Rank Up Rank Down
Feb 3, 2014
Are you saying I shouldn't text nude pictures of myself to my company-wide distribution list?

I'm getting mixed signals here.

I'll go for it. Stay tuned for updates! I don't see how this could go wrong.
+13 Rank Up Rank Down
Feb 3, 2014
I like Albert Einstein's definition of common sense: "the collection of prejudices acquired by age eighteen."
Feb 3, 2014
I generally think of common sense as a response to situation where someone HAS seen a pattern and responds in a thoughtful way. Those without common sense either don't seem to think the pattern applies to them, don't learn after being burned once, or can't decern minor variances in a pattern.

For example, if as a young man you'd gone to your 2nd, 3rd, and 4th professional interviews in casual clothes, that would have been evidence that you lacked common sense.

+4 Rank Up Rank Down
Feb 3, 2014

I think common sense is learned knowledge or ability known by "most" of the people in that particular group or culture. Add a little logic and stir.

It's common sense here, not to stick your tongue on a flag pole. But is that common sense to a Tutsi tribe member? He might say it's common sense to know not to sleep near that little mound over there.

One could say that it's also common sense not to grab a frozen doorknob with wet hands, since you saw "A Christmas Story" you knew about the flag pole, even if you did not grow up here, but you should have enough logic in your brain to make that leap about wet hands.

If you did not grow up in the business culture, you would not necessarily know to wear a suit.

If you were not bullied enough in Middle School (Junior High) you might not have learned to fit in by acting, dressing, and talking like the peer group you were trying to invade.

Most of us learned to camouflage ourselves, and survive.

In fact I wear actual camouflage not to hide in the forest, but to blend in with the people in town.

Abusive, drunk fathers help one learn to blend in pretty fast.

Feb 3, 2014
I just call it "rare sense" whenever I remember to, because life has shown me it's anything but.
Feb 3, 2014
I think the issue is that you're trying to understand common sense by the definition of the two words "common" and "sense." If you do that, everything in your post makes sense. But that's not the correct approach. It is more of a compound word ("commonsense") and the definition of that is usually "ideals and morals that I practice." Neither toads nor stools have anything to do with toadstools, and neither common nor sense has anything to do with common sense.
Feb 3, 2014

[If the term "common sense" is dated, how about "environmental intelligence?" ]

Good start, but I dont like it. We need something shorter and more accessible to common people. 'Environmental intelligence' sounds like the sort of thing a professor would say.
Feb 3, 2014
Not quite sure what you point is - I completely agree with you on your definition of common sense. I grew up with my father telling me "there is nothing quite as uncommon as common sense". It was always obvious to me that common sense was the sum of life experiences. I think most people know that. So what makes the concept dated?
Feb 3, 2014
Maybe instead of "you have either seen a lot of patterns..." it could read, "you have either recognized ..." They are after all available to everyone to notice.

If the term "common sense" is dated, how about "environmental intelligence?"
Feb 3, 2014
I think you're describing exactly what common sense is and then saying it doesn't exist, by pretending people claim it is something else. Nobody thinks common sense is the same thing as instinct. Otherwise we would call it instinct.

Common sense, is the ability to recognize the important patterns specific to the society you are among. What's common sense for a redneck isn't common sense for a city dweller. As you just said, teenagers are especially bad at recognizing some especially important patterns. Thus why we adults say they lack common sense.
Feb 3, 2014
I'm not sure I agree with you.

In my mind, common sense generally involves understanding why you're doing what you're doing, and not being counter-productive. In your example about the interview, common sense (in my mind) is understanding that you're competing with other students for a job, and the purpose of the interview is to demonstrate that you're a better match than your peers for this environment.

But then... that's a part of my head that's always churning -- I try to figure understand other people's motivation -- and I'm frequently lambasted for being manipulative and distrusting. It definitely has downsides. I basically hate everyone because of it.
Feb 3, 2014
...No...even if you're right common sense is a thing, just maybe not the thing we think it is. We like to think that everyone thinks the same way as we do about certain basic things and we label this 'common sense', but experience has taught me that many of our bedrock assumptions about what is and is not 'common sense' simply isnt true, that there are reasonably intelligent folks out there that disagree with your 'common sense' about one, perhaps more than one, thing.

Nevertheless people know what we mean by 'common sense'. That makes it real, but maybe we should come up with a different term for it so folks wont confuse it with things truly everyone knows.
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