Multimedia Inoculates Pseudocontext

I owe Brian Caine a debt of gratitude for flipping my switch on the question of “what is multimedia doing for us, anyway?

Multimedia makes it really, really hard to lie.

Witness David Cox’s toaster regression. It doesn’t work. We thought it was linear. It isn’t. It isn’t worthless for classroom inquiry. Maybe it’s exponential. But the linear model is a dead end.

If you’re writing the problem in a textbook, though, it isn’t a dead end. You grab some clip art of a toaster. You create a table with values that are linear because who’s going to stop you? Even though the real context isn’t linear, you’re the god of your textbook’s pseudocontext.

Then you fabricate a conclusion that supports the pseudocontext.

For whatever other good it does for problem posing, multimedia keeps you honest. How do you (easily) film pseudocontext? How do you take a picture of a premise that is false? Even harder, how do you take a picture of the conclusion of that false premise in a way that doesn’t belie the premise itself?

I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. What about scams and hoaxes? Can we classify this as pseudocontext.

    This Power Balance demonstration comes to mind.

    I think this video shows us pictures of a premise that is false.

    ::context that is flatly untrue:
    an experiment is conducted with only one experimental variable (band and no band) – all other variables are kept constant

    ::operations that have nothing to do with the given context: Being a science investigation, we don’t have operations that are unrelated to the context. However, terms like energy, frequencies, fields, and holograms are thrown into the description of this investigation. These terms have nothing to do with human balance, strength, and flexibility.

    Yet, extraordinarily claims are driven home with the help of multimedia.

    However, I don’t feel like I have a firm grasp of what pseudocontext is outside of math.

    Can you open up the description of pseudocontext with examples in different subject areas?

    BTW: here is a description of a more scientific investigation of Power Balance.

  2. Or, you can then run the video and say “does the linear model match reality? If not, why?” and students can then begin to think about non-linear models, which is quite exciting since linearity is all that math talks about for years.

  3. As a textbook writer, I take offense. Obviously someone else in editing and layout would be the one to grab the clip art of the toaster, and the book’s answer key should only list the odd-numbered problems.

    (Seriously though, this is a horrible context and I hope that if I were writing about linear models, I would choose something a lot more appropriate. Besides, my own toaster actually DOES have a linear model for its 7 settings!)

  4. You know you’ve left the rhetorical barn door open too wide when both Dina and Joe pounce on the same thread. I gave it another pass though I’m not sure anyone’s going to be any more convinced over there.

    Bowen: … the book’s answer key should only list the odd-numbered problems.

    Rookie error right there. Good catch.

  5. What’s the point of identifying pseudocontext in a Math class alone? This should be a joint effort by all the sciences and math to point out that while a model constructed by humans in the language of mathematics, predictions are eventually going to differ when enough scrutiny is given and the model not adjusted for those discoveries.

    Richard Feynman makes an interesting point when an interviewer asks “Why do magnets repel or attract?” that since laws of physics are based on observations, the question of “Why does X happen?” sets you up for an infinite series of questions until eventually the person honestly says “I don’t know.”

    Models are imperfect, that’s why we refine them. And by “imperfect” I mean as a Mathematics instructor would count points off an exam for a student writing an answer in decimal approximation rather than keeping it as a (reduced) exact expression. Models of the universe are made arbitrarily accurate through application of study and research so these imperfect models can make useful predictions within an allowed measure of error.

    And, seeing as how a student may be very naive to a subject, one might find advantage to teaching about George Washington’s proverbial cherry tree before moving on to a general discussion of civics and the social contract.