http://bit.ly/1yBDMbb January 4, 2015
I was recently contacted by a student who will be working as a teaching assistant for an upper-level CS course. He remembered that, during a visit to his campus, I had said that the way courses are taught is just as, if not more, important than the race, gender, ethnic background of the instructor. His question was whether I had any advice for him and his fellow TAs about how they could "conduct ourselves or talk about the course material in order to help foster as inclusive and welcoming an environment as possible."
Here is the advice I gave, which I think can be helpful for faculty as well as for TAs, lab assistants, student help desk workers, and others.
I am sure this is not a comprehensive list. What do you do in your classes? What can you add to my list? Post your ideas to the comments. Thanks!
http://bit.ly/1g39mAX March 27, 2014
Andy Ko wrote a recent blog post (http://bit.ly/1iVxF3A) with an important claim: "Programming languages are the least usable, but most powerful human-computer interfaces ever invented." Ko argues the "powerful" part with points about expressiveness and political power. He uses HCI design heuristics to show how programming languages have poor usability. Obviously, some people can use programming languages, but too few people and at great effort.
I see that his argument extends to learnability. There are two ways in which programming languages have poor learnability today—(1) in terms of expectancy-value and (2) in terms of social cost.
What is the benefit of a closure? Eugene Wallingford tweeted a great quote the other day:
Educational psychologists measure the cognitive load (http://bit.ly/1lSmG0f) of instruction, which is the effort that a student makes to learn from instruction. Every computer scientist can list a bunch of things which were really hard to learn, and maybe could not even be imagined to start, like closures, recursion in your first course, list comprehensions in Python, and the type systems in Haskell or Scala. http://bit.ly/1BMu8QD
Expectancy-value theory (http://bit.ly/1sctSGD) describes how individuals balance out the value they expect to get from their actions. Educational psychologists talk about how that expectation motivates learning (http://edcate.co/1iefV80). Students ask themselves, "Can I learn this?" and "Do I want to learn this? Is it worth it?" You do not pursue a degree in music if you do not believe you have musical ability. Even if you love art history, you might not get a degree in it if you do not think it will pay off in a career. Most of us do not learn Dvorak keyboards (http://bit.ly/1jvaFNC), even though they are provably better than Qwerty, because the perceived costs just are not worth the perceived benefit. The actual costs and benefits do not really play a role here—perception drives motivation to learn.
If you cannot imagine closures, why would you want to learn them? If our programming languages have inscrutable features (that is, high cognitive load to learn them) with indeterminate benefits, why go to the effort? That is low learnability. If students are not convinced they can learn it and they are not convinced of the value, then they do not learn it.
The social cost of going in a new direction. I was at a workshop on CS Education recently where a learning scientist talked about a study of physicists who did their programming in Fortran-like languages and only used arrays for all their data structures. Computer scientists in the room saw this as a challenge. How do we get these physicists to learn a better language with a better design, maybe object-oriented or functional? How do we get them to use better data structures? Then one of the other learning scientists asked, "How do we know that our way is better? Consider the possibility that we're wrong."
We computer scientists are always happy to argue about the value of one programming paradigm over another. But if we think about it from Andy Ko's usability perspective, we need to think about it for specific users and uses. How do we know that we can make life better for these Fortran-using physicists?
What if we convinced some group of these Fortran-using physicists to move to a new language with a new paradigm? Languages do not get used in a vacuum—they get used in a community. We have now cut our target physicists off from the rest of their community. They cannot share code. They cannot use others' libraries, tools, and procedures. The costs of learning a new language (with new libraries, procedures, and tools) would likely reduce productivity enormously. Maybe productivity would be greater later. Maybe. The value is uncertain and in the future, but the cost is high and immediate.
Maybe we should focus on students entering the Fortran-using physics community, and convince them to learn the new languages. Learning scientists talk about student motivation to join a "community of practice" (http://bit.ly/1kDIhFJ). Our hypothetical physics student wants to join that community. They are learning to value what the community values. Trying to teach them a new language is saying: "Here, use this—it's way better than what the people you admire use." The student response is obvious, "Why should I believe you? How do you know it's better, if it's not what my community uses?"
Solution: Focus on usability. Communities change, and people learn. Even Fortran-using physicists change how they do what they do. The point is that we cannot impose change from the outside, especially when value is uncertain.
The answer to improving both usability and learnability of programming languages is in another HCI dictum: "Know thy users, for they are not you." We improve the usability and learnability of our programming languages by working with our users, figuring out what they want to do, and help them to do it. Then the value is clear, and the communities will adopt what they see as valuable.
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