The pedagogy of the assignment operator

I can see that I am going to have to set a little context because I wanted
to anchor the discussion in the teaching of statistics, and not of R as a
language. I think the issues are different in the two. One big problem in
the former is that symbols can engender fear in the students.

A few years ago I was taken off the teaching of a large first year business
statistics course. The clinching incident in this decision mentioned by my
then chairperson was the use ( in a side-discussion ) of the mathematical
summation sign ( upper-case Greek sigma ). ?I don't think my chairperson was
wrong. In the context of that course what I should have done was illustrate
my point with a column of data in an Excel spreadsheet.

If \Sigma upsets business students with its suggestion of abstract
mathematics, I think many other statistics students find <- somewhat
suggestive of abstract logic or theoretical computer science, favourite
subjects of an epsilonic proportion of the large classes I used to teach.

I teach smaller classes now and my students come to me with previous
exposure to Minitab which uses = for assignment. I use = both to avoid any
of the symbol-fear that I spoke of, and also because they are used to how
assignment works in Minitab. (For maybe half of the students, Minitab would
be the only computer language that they would have met.)

I will come clean and admit that I have another reason for not liking R.
The symbol <- suggests the right-to-left direction of the assignment
strongly and appropriately. But I read from left-to-right and I get startled
by an arrow coming at me from the unseen future and feel a second or two of
cognitive dissonance.

I actually rather like the right-pointing -> assignment as the directions of
reading and of computation agree. It would be a bit idiosyncratic to use it
in code though. I find it useful in interactive R when I have typed and
evaluated a complex expression and realise that I really should have
assigned it to something. After the up-arrow key -> lets me do the needed
assignment on the right of the expression.