Teaching Dogma

This post is about how it is important to avoid taking rigid pedagogical attitudes while teaching.

Having associated with academia (as a student and a professor) for almost 50 years now, I have come across several teachers who proclaim various types of unbending attitudes which they sincerely believe in and proudly implement in the classroom. I feel these actions are sub-optimal, if not downright disastrous for some students, as teaching is an art which requires open and flexible approaches, and not a science which is susceptible to formulas or one-size-fits-all techniques.

Below I will discuss some approaches I have encountered in my time so far, and why I think they ought to be more nuanced. A discipline that helps analyze effective physics teaching approaches is called Physics Education Research (PER) - likely equivalents exist for other disciplines. I will also include some examples of how decades of data analyzed by PER has revealed counter-intuitive findings that challenge traditional physics teaching assumptions.

1. "I always try to mould my students in my own image": This is a statement emanating from blind intellectual hubris and lack of recognition that every person has their own way of learning. Also, there is usually a distribution of abilities in any class sample and one cannot try to shape them all into a single type. Finally, the texts, techniques and applications of the subject (esp. physics) upgrade over time, and we should be looking to incorporate these improvements into our pedagogy and not use upon the new generation (only) the old techniques that were used on us.

   
   

2. "I always give open book exams": This is motivated by the desire to minimize the role of memorization in testing. I am generally in support of such a move. However, one has to think carefully about what is being tested. Open book exams are good for upper level courses, in my opinion, as the understanding being tested is advanced (so we we should not burden them with remembering basic things).

   
   

   However, open book exams are counter-productive if foundational understanding is being tested, as in the lower level courses. In order to understand this, we have to recognize that any test of foundational understanding involves memory demands unavoidably. For example, if I am testing someone for their fundamental ability to communicate in English, this means I am also testing to see if they have memorized a large number of words in that language (and if they can use them to communicate coherently). Allowing them to use a dictionary on such a test would be counter-productive. It would basically make the test meaningless.

   
   

   On a practical level, I see students get confused if they put too many formulas in their allowed crib sheet - imagine allowing them a whole book to parse for the exam!

   
   

3. "Students who get A's on exams are competent": PER has shown that algorithmic success can hide conceptual failure. Students who score an "A" on standard, math-heavy exam often fail basic conceptual questions. E.g., on basic mechanics tests, they can perfectly apply complex calculus formulas while simultaneously believing a tossed coin experiences a "force of the throw" keeping it in the air [1].

   
   

4. "If I give an excellent lecture, students will understand everything": PER has shown that passive listening can leave deep-seated physical misconceptions untouched, and that students filter the lecture through their existing intuitive biases rather than updating their mental models [2].

   
   

5. "Some teaching is always better than no teaching": PER (this was a study carried out in Japan) has shown that partial learning can have a regressive effect. In certain topics (like fluid mechanics), post-instruction test scores can occasionally drop lower than pre-instruction scores.

   
   

   This happens because instruction introduces new terms that confuse students, leading them to abandon an initially correct "lucky guess" or basic intuition in favor of a misapplied new scientific word [3].

Summary

As teachers, we are all passionate about teaching well, but need to be careful about pressing biases forward to the detriment of our students. We need perhaps to keep the intellectual version of the Hippocratic Oath, administered to doctors, in mind - our first duty is to cause no harm. Also, we need to acknowledge that the human brain is a subtle mechanism and displays variations from person to person that we need to respect. Overall, as long as teachers are willing to be learners, teaching is in good hands.

[1] American Journal of Physics, 70, 759 (2002).

[2] American Journal of Physics 53, 1043 (1985).

[3] Phys. Rev. Phys. Educ. Res. 17, 020120 (2021).