Here’s one thing that you do as a mathematician a lot: change the assumptions and see how wildly the conclusions change. You usually start with lots of assumptions, and then see how things change when they are taken away one by one: what if the ring isn’t commutative? What if it doesn’t have a “1”?

Of course, it’s easy enough to believe that we can no longer prove the same theorems when we don’t start with the same kinds of mathematical set-ups. But this kind of thing can also apply to non-mathematical scenarios as well.

So, for example, I’ve long thought that the “marshmallow” experiment is nearly universally misunderstood: kids wait for the marshmallow for exactly as long as it makes sense to them to wait. If they’ve been brought up in an environment where delayed gratification pays off, and where the rules don’t change in the meantime, and where they trust a complete stranger to tell them the truth, they wait, and otherwise they don’t – why would they? But since the researchers grew up in places where it made sense to go to grad school, and where they respect authority and authority is watching out for them, and where the rules once explained didn’t change, they never think about those assumptions. They just conclude that these kids have no will power.

Similarly, this GoodBooksRadio interview with Linda Tirado is excellent in explaining the rational behavior of poor people:

Tirado just came out with a book called Hand To Mouth: Living in Bootstrap America and was discussing it with Dr. John Cook, who was a fantastic interviewer. You might have come across Tirado’s writing – her essay on poverty that went viral, or the backlash against that essay. She’s clearly a tough cookie, a great writer, and an articulate speaker.

Among the things she explains is why poor people eat McDonalds food (it’s fast, cheap, and filling), why they don’t get much stuff done (their lives are filled with logistics), why they make bad decisions (stress), and, what’s possibly the most important, how much harder work it is to be poor than it is to be rich. She defines someone as “rich” if they don’t lease their furniture.

I’m looking forward to reading her book. As the Financial Times review says, “Hand to Mouth – written with scorching flair – should be read by every person lucky enough to have a disposable income.”