## Friday, September 29, 2017

### On music, mathematics and teaching.

I'm a perpetual student when it comes to my guitar-playing. I started off learning acoustic guitar, and taught myself a little bass in college. When I was in the college band our music advisor played some classical guitar and that got me hooked.

I've had a number of teachers through grad school and beyond, but I've always plateaued out at a level where I'm competent but no better. At some point I realized that what motivated me to play was the right kinds of music (this I also learnt when watching my children learn an instrument), and that inexorably led me to my new quest: learning flamenco guitar.

Flamenco is a very passionate style of playing - and classical guitar can seem bloodless and sedate in comparison. It also requires many different right hand techniques that are not common in classical guitar problem.

The net result is that I'm back to being a beginning student again - struggling with mechanics, hand position and note playing. It's a lot of frustration with the occasional moment of transcendence. I whine at my teacher in the way students whine at me, and he's sneaky enough that now he just asks me "so what would you tell your own students" and that shuts me up.

Which brings me to the point of this post (what??? posts need a point?). We spent a lesson last week talking about extracting expression and feeling from the instrument. I kept asking him about what tools I could use (beyond the usual tone control by moving up and down the fretboard and using volume) to express more emotion, and what emotion that would be. His response was first to show me this beautiful video of an interviewer "talking" to Paco De Lucia's guitar

and then explain to me that I have to dig deep within myself to find the way I can relate to the music.

And then it hit me (painfully). Aditya Bhaskara and I are running a theory seminar on reading classic theory papers where (much like my previous seminar) there's a strong emphasis on getting to the core ideas and intuitions that drive a result. I'm constantly exhorting students (even more so than Aditya - I think it's interesting to see how different people absorb messages from a paper) to find the core intuition in the paper and be able to express it in a short "story" almost.

And that's essentially what my teacher is exhorting me to do. In both cases, the expert is trying to get the student to transcend the purely mechanical aspects of (reading the paper/playing the instrument) and get to the deeper (mathematical/emotional) truth of the (paper/piece). And it's hard precisely because the student in either case is still struggling with the mechanical, and doesn't yet have the facility with the tools to let them fall away.

Does this mean I'll be a more enlightened teacher? I doubt it :). But I do have a little more sympathy for my students.

### "X is a social construct" and the perils of mining behavior.

After the infamous Google memo (and frankly for much longer if you work in algorithmic fairness), the idea of something being a "social construct" has popped up again, and I will admit that I've struggled with trying to understand what that means (damn you, focused engineering education!)

Ta-Nehisi Coates' article about race is a short and excellent read. But I also want to highlight something much closer to home. BYU Radio's Julie Rose did an interview with Jacqueline Chen (at the U) on her recent work on perceptions of race in the US vs Brazil.

The interview is here (and it's short - starting at around 20 minutes in) and in it Prof. Chen very masterfully lays out the way in which race is perceived and how it changes based on changes in context. The interview is based on a recently published paper ().

One important takeaway: the way in which one's racial identity is perceived varies greatly between the US (which appears to be influenced by parental information) vs Brazil (where skin color appears to be the dominant factor). More importantly, the idea of race as immutable vs changeable, a categorical attribute versus a continuous one, all vary.

And that's what we mean by saying that X (here, race) is a social construct. It's not saying that it's fictitious or less tangible. But that it's defined by the way we talk about it in society.

Why is this important? When we collect data as a way to predict behavior, we're making an implicit claim that behavior can be predicted (and explained) by intrinsic and often immutable descriptors of an individual. We use (or don't use) "race" as a feature when building models.

But this itself is a huge assumption! It assumes that we can intelligently ascribe features to individuals that capture these notions, and that they are defined solely by the individual and not by context. The brilliant Medium article about the paper that claimed to predict criminality from facial features makes this point very well.

But do we capture the entire history of environmental factors that make up the story of an individual. Of course not. We essentialize an individual into a collection of features that we decide captures all their relevant traits for the purpose of prediction, and then we build a model that rests on this extremely problematic idea.

Much of the work I do on fairness can be reduced to "check your data, and check your algorithm". What we're also thinking about (and that directly speaks to this issue) is "check your features".

It turns out that way back in 1921, Walter Lippman had something interesting to say about all of this. From a longer essay that he wrote on the importance of frames as mediating how we perceive the world (and it says something about fake news and "true facts" as well):
And so before we involve ourselves in the jungle of obscurities about the innate differences of men, we shall do well to fix our attention upon the extraordinary differences in what men know of the world. I do not doubt that there are important biological differences. Since man is an animal it would be strange if there were not. But as rational beings it is worse than shallow to generalize at all about comparative behavior until there is a measurable similarity between the environments to which behavior is a response.