In the languages that I mentioned (js,lisp,py), you will write a small function in the interactive shell (repl) and play with it and tinker it until it works perfectly. Then you'll write another function that uses this and other such functions etc. You'll build functions on top of functions until you have a fully usable system. As you know, this is bottom-up programming. While you can continue to improve things and refactor code as much as you want, at no point do you have to throw everything out and start clean. You don't lose any work.

I don't know much Objective C. I've just written some tiny iPhone apps in it. But my feeling is that it strongly encourages top-down programming, which results in the programmer having to do the things mentioned in the article (plan ahead, rewrite from scratch etc).