Why should non-CS majors learn functional programming?

In my research, I’m most interested in the non-CS majors, the ones who learn computing because it makes them more productive (see where I make that argument) or because they want to make themselves more marketable (see Eric Robert’s post) or because they will live and work (as I predict) in the fat line between programmers and users (see post here).  A recent article in the CACM suggests that all non-CS majors need to be learn (let’s not use the “be exposed” euphemism — there’s no sense in “exposing” someone to something unless you’d like them to learn from it) “functional programming languages [and] the declarative programming paradigm.”  I’m willing to consider that, but why?  The quote below says, “they allow programmers to do more with less and enable compilation to more efficient code across a wide range of runtime targets.”  I’ve been studying non-CS majors who program for a lot of years, and I’ve never heard any of them say even once that they want to “enable compilation to more efficient code across a wide range of runtime targets.”

So let’s consider the “more with less.”  Do we buy that what what non-CS majors is to be able to get more expressive power with fewer keystrokes?  I don’t see the argument for that.

• Brian Dorn studied graphic designers who program, and found that assignment was fairly hard for them to learn (see his CHI 2010 paper).  Surely, there’s not much that has fewer characters than that.
• Neil Brown has been mining the BlueJ Blackbox data for empirical data on what students get wrong most often (see his ICER paper).  I was surprised to learn that confusing & for && and | for || is pretty common.  Those are pretty easy to type, short, and seemingly error-prone expressions.
• We have Thomas Green’s fascinating result that that IF P THEN … END P; IF NOT P THEN … END NOT P. is not just better than IF P THEN…ELSE.…  It’s ten times better — novices do better by a magnitude if they avoid ELSE.

My suspicion is that non-CS major programmers value understandability and fewer errors, over fewer keystrokes and more power.

I like functional programming and would be interested in a good argument for it for non-CS majors.  I don’t see it here.

Second, would-be programmers (CS majors or non-majors) should be exposed as early as possible to functional programming languages to gain experience in the declarative programming paradigm. The value of functional/declarative language abstractions is clear: they allow programmers to do more with less and enable compilation to more efficient code across a wide range of runtime targets. We have seen such abstractions gain prominence in DSLs, as well as in imperative languages such as C#, Java, and Scala, not to mention modern functional languages such as F# and Haskell.

via Teach Foundational Language Principles | May 2015 | Communications of the ACM.