That old topic. Ironically, I find people who work with math ( chosen to work with math, that is) to probably be quite unqualified to truly understand the problem. He opens by saying that learning avoiding mistakes before any bigger concepts is a major root of this but then again, people do make mistakes in math (even math professors) and it's a field where any mistake can completely invalidate the work. Also most pe…
The problem is that an emphasis on avoiding mistakes leads to paralysis. Though he phrases it differently. Students don't want to be wrong so they just don't instead.
As he points out later in the piece, learning from our mistakes is key. If I never learned to walk because I fell the first time and failed walking class, I'd be crawling even today. An overly negative assessment of the students' works, an overemphasis on right and wrong, rather than correction and expansion to different methods when some method has failed a student, ends up producing many students who can't do math.